BERLIN FLAK TOWERS: HUMBOLDTHAIN PARK

HUMBOLDTHAIN PARK BEFORE WWII

Similar to several districts beyond the Berlin city center, Gesundbrunnen did become a part of the city as late as the mid-XIX century. ‘Gesundbrunnen’ may be translated as a ‘healthy spring’, thus referring to a mineral spring, which had once transformed a suburb with low population density into a spa destination. The very first documented mention of the underground spring, which was regarded to have live-preserving qualities, goes as far back in history as 1748. While in the previous two centuries the area had been known as shepherd lands for local nobility, in 1757 the well-known Frederick II ‘The Great’ provided both his goodwill and sponsorship for building up the healthcare facility. The new recreational complex would be completed in 1760 on today’s site of the Pankstrasse metro station and would be marked on Berlin maps as ‘Gesundbrunnen’. The guests of the health resort were welcomed to rent one of the houses and take daily procedures and walk within the facility which looked like a park. Both the spring and the resort would exist until the late XIX century. 

As early as 1861 while the area was still widely appraised as a health-giving destination and for its breweries, Wedding and Gesundbrunnen suburbs were incorporated into Berlin’s area as Luisebrunnen after Louise of Mecklenburg-Strelitz (1776-1810), a queen of Prussia. Four years later, in 1865, the city authorities finally made up their mind to develop the vast open air to the south of Luisebrunnen and to the East of Wedding and turn it into a public park for the growing number of local working-class districts. Gustav Meyer, already a recognized landscape architect, was chosen to create a new Berlin park. He was known not only for the reshaping of the garden suburbs in Potsdam but also due to his supervision of the creation of the Volkspark Friedrichshain (a site for two anti-aircraft Flak towers in WWII) back in the 1840s. In total, only the preparatory period took Meyer fours years and the future ‘Volkspark Humboldthain’ was founded on August 14, 1869, on the 100th birthday of Alexander von Humboldt (1769-1859), a famous German naturalist and geographer who had passed away ten years before. 

According to Gustav Meyer’s vision, this newly created park in Berlin was to become not just another recreational and leisure area for the local working-class population, but also should serve for educational purposes and a link to Humboldt was intensified. Toward the end of the works in 1786, ‘Volkspark Humboldthain’ (public park Humboldt’s grove) was made a piece of landscape art. With the final expanses of enormous 340 000 marks, the park was shaped with dozens of walking alleys, large open yards similar to city squares, and playing grounds for children usable as open-air skying sites in the winter months. The park was planted with unique trees and bushes from both the Americas, Asia, and Africa, with informational boards next to the most precious species. ‘Volkspark Humboldthain’ had an irrigation system for supplying the area with water. In 1895 a Geological Wall for children, with layers of rocks from different historical periods was opened. 

In 1893 the park became a home for Himmelfahrtkirche (Church of the Ascension) in neo-Romanesque style, which was built to cover the religious needs of the ever-increasing Christian population in the neighborhood. The city plan of Berlin from 1872 reveals a railway spur to the north of the park as well as a vast industrial area to the south. A circular railway around Berlin, ordered for construction by King Wilhelm I, was opened on January 1, 1872, with a train depot on the site of the modern Gesundbrunnen station (opened in 1930). As for the industrial district to the south, a large slaughter facility as well as ‘Neuer Berliner Viehmarkt’ (new Berlin cattle market) had been the headache for the locals for years with its smell infiltrating a favorite park. Toward the 1890s the slaughter enterprise sank into degradation and for some time it was marked on the city plans of Berlin as ‘Lagerhof’ (storage yard). In 1895 the former facility was bought by the “Allgemeine-Electricitäts-Gesellschaft“ electrical company, better known as AEG. It was in the 1890s when the electrical industry intensified the industrial development of Berlin. AEG built several new buildings aimed at manufacturing electrically-powered machinery, railway equipment, and electric household goods. The only surviving erection of that period, known as ‘Beamtentor’ (Clerk’s gate) could be still found in the east part of the former industrial area, facing ‘Brunnenstrasse’ street. At the same time, a new Gustav-Meyer-Allee was laid along with one of the former alleys in the southern part of the park with a rose garden opened here in 1901 opposite the directorate building of AEG. 

‘Volkspark Humboldthain’ retained its status as a favored recreational area in the XX century as well, particularly with the increase of the working-class population after the creation of AEG. Humboldthain thus became one of the most favored leisure areas in Northern Berlin. Toward 1925 only one-third of the territory of Wedding (1300 hectares) was built up with its 337 000 population, 57% among which were workers and 20% white-collars. The density was extremely high and the green zones such as Humboldthain park were of great value. It is important to note that in the years of the late Weimar republic, the Nazi party (NSDAP) was not the leading political movement among the local population. Even the March 5, 1933 election showed moderate support for Hitler’s party even regarding the suppression of the opposition. NSDAP got less support in the Wedding district (former Gesundbrunnen was a part of it) with 25.9% votes (the overall Berlin result was 31.3%), than an incredible 39.2% to KPD (‘Kommunistische Partei Deutschlands’, German communist party). Due to the dominating role of the communist party, for some time the district was known as ‘the red Weidding’. 

 

A HELL FROM SKY: CIVIL AIR DEFENSE IN THE THIRD REICH

The ‘Great War’ or better known nowadays as the First World War, left the hearts of the entire generation with not only glimpses of trenches full of rainwater and lice, and hunger in the cities. The population of humiliated Germany, deprived of its air forces, was frustrated with the prospect of using aviation against the civilian population in future wars in Europe. The German army had an experience of using giant Zeppelins and bombers to attack British cities and after the war, there was an understanding, that such practice may be extensively used in the upcoming conflicts. The most painful phobia was the possible use of poisoned gasses, even after the Geneva protocols adopted in 1925. In the years of the Weimar Republic, the scarce number of anti-aircraft forces were subordinated to the Reichswehr, particularly to the field army with an aim of defending the units on the ground and not protecting the civilian population. In the 1920s the protection of the population from the air had more of an informational nature than practical means. Only a slight number of people were informed how to use the protective masks properly and the air-raid-protection services were at this time mainly supervised by the Ministry of the Interior efforts. 

After Hitler’s ascension to undisputable power in Germany, the rebirth of the army, and the rearmament for future expansion, the mobilization of the economy and industry, of popular opinion, became the leading tendencies in the 1930s. When it came to the issue of air defense and setting priorities between the passive and active measures, Hitler was and would be later focused on using aircraft and anti-aircraft guns as not only an initiative in the war but also as an illusive method of air defense of Germany. Already in 1933, Hermann Goring announced the creation of the ‘Reichsluftschutzbund’, or ‘RLB’ (National Air Raid Protection League), whose membership would reach 15 million members before the outbreak of WWII. The ‘League’ was led on a regional basis: province-region-area-district (Landes-Gaue-Kreis-Orts). The new voluntary organization absorbed the former ‘Verein Deutscher Luftschutz’ or ‘DLS’ (the Association of German Air Raid Protection, est. 1927) and ‘Deutsche Luftschutzliga’ (German Air Raid Protection League, est. 1931). 1934 witnessed the installation of the air alarm system in Berlin. 

While the reborn of the German air had been implemented since early 1933, on paper the Luftwaffe was created in March 1935 in parallel to the renouncing of the provisions of the hated (by Hitler and the Nazis) Versailles Treaty. The matter of air defense of the Third Reich was now the primary responsibility of Hermann Goring, who had absorbed the command of the former flak forces of the field army formations. Since 1935 the national air-raid protection was led by a special inspectorate of the Führungsstab 1A (a part of the Luftwaffe general staff). In August of the same 1935, Hitler signed the so-called ‘Luft Verteidigungs Gesetz’ (the air-raid protection law), which literally obliged every German citizen to participate in the air defense measures. Concurrently, the program of German rearmament allowed the anti-aircraft forces with 1,900 88mm heavy Flak guns, supplemented by 20mm and 37mm light Flak guns and searchlights, which would become the basis of the German national air defense. In total toward mid-1939, the Luftwaffe ‘flak’ (air defense) forces possessed 2600 heavy guns of 88mm and 105 mm which was a far greater figure than compared to the British 1300. The figure would rise to a previously unbelievable 13,500 heavy guns toward February 1944. In 1940, at least 528 000 men served in the flak units. 

The factor for focusing on passive air defense was the Spanish Civil War (1936-1939) with the use of bombers, particularly German, against unprotected cities. While the Air protection law was signed in 1935, the first major decree defining the future air defense policy throughout the war was issued in Germany as late as May 1937. During this period, several organizational bodies were created to supervise the erection of air shelters throughout the Third Reich. ‘Werkluftschutz’ or ‘Industrial air-defense service’ was created to supervise the construction of large air shelters within factories and next to large enterprises to protect the industrial background of the state during the War. The enterprises with contracts for military equipment as well as the large railway hubs and airports were now top priorities for air defense. The so-called ‘Erweiterselbschutz’ or ‘extended self-protection service’ was aimed at supervising building shelters for smaller industrial buildings, and public and private buildings for the population. Finally, the ‘Selbschutz’ or ‘self-defense service’ encouraged the erection of smaller private air-raid shelters. In 1939 up to 80% of the Luftwaffe resources were devoted to the defense of the home front compared to 20% for tactical air defense of the army. 

With the outbreak of the full-scale World War in September 1939, the German police formations were responsible for the carrying out of air defense instruction by the population, for example for detaining night-time blackouts. During the campaign in Poland, the German air forces carried out disastrous raids against Warsaw and Polish cities in the absence of adequate countermeasures. The period of the so-called ‘Phony war’ between September 3, 1939, and May 10, 1940, witnessed no direct threat to the German cities from the air. While the French aircraft were conducting reconnaissance flights over the near-border territory and dropping leaflets, the British RAF was restricted to limited air raids against the military, particularly shipping targets along the German coast. The German anti-aircraft defense of the coastline proved to be effective enough. With the outbreak of the French campaign in May 1940, some raids were conducted along the border but primarily against the military target and some drops on German cities were rather accidental than systematic.

In parallel to the fact of the severe bombardment of Rotterdam on May 14, 1940, Luftwaffe did not conduct massive air raids against the large French cities, particularly not to provoke enemy reprisals against German civilians. More than that, the lightning successes on the battlefield in May-June 1940 made such air raids unnecessary from the military perspective. It was not until the ‘Battle of England’ and the first raids against the British cities, which opted Winston Churchill launched air strikes against Berlin, which unleashed the mutual air campaign between the two rivals, aimed not only at military objectives but primarily against the capitals: London and Berlin. Less than a year after the start of the war, on the night of August 26, 1940, the Berliners experienced the first air raid of the British RAF. While only 22 among the 95 aircraft were successful in dropping bombs above Berlin without significant damage to the city, the Germans were now brought to the understanding that the capital is not as defended as it had been proclaimed before. More than that, the German campaign of air bombardment of London after the August 26 raid on Berlin, meant the inevitable attack against the German capital. 

In the weeks that followed that first air bombardment of Berlin, the air alarms became a common reality almost every night in the city and Hitler himself now had to react to the inadequate air protection of Berlin. The first major decision on the erection of the huge flak towers in Berlin was made by Hitler during the meeting on September 9, when he ordered to build of giant constructions to protect the city from the air. A week after, Hitler gave Albert Speer his own sketches of the towers regarded him as a new example of the grandiosity of the Nazi regime. As early as September 20, 1940, there was another meeting between Speer and Fritz Todt, the Reich Minister for Armaments and Munitions (the post which speer would inherit in 1942) and the Luftwaffe staff on the erection of the anti-aircraft towers. Speer was in power to choose the locations for the towers, the classification, and the design, and Todt was to supervise the construction process and technical requirements suggested by Luftwaffe. The need to speed the process up was also ‘encouraged’ by a new RAF air raid on Berlin on the night of September 24, 1940, when 84 of 199 planes reached the city to unleash their bombs. It is interesting to note that in these two months of August-September 1940 the German flak gunners shot 87 000 rounds, another 67 000 in November with a zero-hit ratio. 

Hitler’s plans to protect Berlin by means of giant anti-aircraft towers were not even a health measure but a minor solution for a tiny part of Berlin’s 4.3 million population. The continuing air raids of the British RAF forced Hitler on October 10, 1940, to establish the so-called ‘Führer-Sofortprogramm’ (“Fuhrer’s emergency program”), an ambitious national program to protect the civilian population in Germany from the air raids during the war. Similar to many other ideas in the Third Reich, at least on paper the program looked impressive by supposing the construction of shelters for 35 million people in 90 largest cities in Germany, particularly with a population over 100 000. The construction experts calculated that the erection of 6000 large bunkers would demand 200 million cubic meters of concrete. The figure was not achievable even for the megalomaniac ambitions of the Third Reich with its practice of mobilizing resources. It surpassed the amount of concrete, which Germany used since the end of WWI. For a better understanding of what 200 million cubic meters mean, between 1942 and 1944 all fortifications of the ‘Atlantic Wall’ in the West consumed as much as 17 million cubic meters, and the well-known Maginot line, built by the French in the 1930s, demanded only 1.5 million, less than 1% of the planned consumption for the ‘Führer-Sofortprogramm’. 

When all calculations were carried out, it was decided to divide the whole program into three phases based on the prioritization of the targets. The so-called ‘Luftschutz-Orten. 1’ (Air raid places order 1) thus included 70 German and Austrian cities with populations over 100 000 people and military factories. This initial phase was to supply protection to only 5% of the population in these cities, primarily in the city centers, governmental districts, and next to key military manufacturers. This stage was planned for carried out in one year between November 1940 and November 1941. The man directly responsible for the supervision of the ‘Führer-Sofortprogramm’ was Dr. Kurt Knipfer (1892-1969), a ministerial director of the civil air defense department in the Reich Ministry of Aviation since 1937. While the construction process was assigned to Organization Todt (OT), in contrast to other ambitious military construction projects such as the Atlantikwall’, the fulfillment of the “Fuhrer’s emergency program” would have a more decentralized nature with the emphasis on local municipal governments. 

While the giant flak towers based on Hitler’s megalomaniac sketches were rather another attempt to demonstrate the grandeur of the Third Reich, the adequate air defense of the civil population demanded more practical means. The calculations revealed that the erection of the above-the-ground shelters was a faster and less consuming solution than that of the underground bunkers. There was also a direct linear correlation between the size of the bunker and the saving of the resources. The larger the shelter was, the fewer cubic meters of concrete were needed for every human being inside. The practical fulfillment of the ‘Führer-Sofortprogramm’ thus focused on the construction of the ‘Luftschutzbunker‘, also regarded as Hochbunker (“Tall bunker”) because of its above-ground type. On the other hand, even such a practical ‘people’s bunker’ was strongly criticized by some Luftwaffe specialists who insisted on the creation of a greater number of small shelters with less protection but accessible for the larger proportion of the population. These experts also suggested the creation of firewalls between common accommodational buildings. In practice, the most common form of civil air defense shelter during the War was the reinforced basements under the buildings, regarded as of ‘low standard’ of protection and incapable to protect people from a direct bomb hit. In contrast, the typical ‘Luftschutzbunker‘ with a reinforced roof of 1.4 meter thick was supposed to stand against a 250 kg bomb (at the time when British bombers already practiced 2-4 ton bombs). Such widely used ‘Luftschutz Kellar’ (basement air-raid shelters), reinforced with steel and wood, could accommodate up to 100 people at once, conventionally inhabitants of large apartment buildings. 

The decentralization of the construction supervision for creating air raids shelter for the population would prove to be effective means. Despite several strategic decisions made by Hitler in September-October 1940, the German dictator would show no significant interest in the faith and lives of the Germans from the air, outside his few admiring comments regarding the flak towers. The things which did not provoke his imagination, such as routine day-by-day war and the lives of the people, were left beyond Hitler’s attention during the war, especially in its final stages. The German fuhrer was illusive in the idea that the Luftwaffe under his right-hand Goring would prove to be as effective a means of defense as the RAF during the Battle of Britain in 1940-1941. As I have stated above, enormous resources were spent on utopian projects such as the ‘Western Wall’ on the Atlantic coast, which later proved to be insufficient during the Allied invasion in 1944.

On the contrary, even with the lack of resources, it was the active involvement of the local authorities in the regions, which allowed for a significant decrease in the death toll of the German civil population during Allied air bombardments in WWII. It is hard to imagine the number of victims if the air defense of the Reich relied on Hitler’s inadequate fantasies. By conservative estimates, at least 300 000 of the German civil population were killed and 800 000 wounded as a result of the Allied campaign with its 1.2 million tons of bombs, and the German civil air defense definitely limited these figures. Berlin itself suffered 450 air raids dropping 45 000 tonnes of explosives with estimated 50 000 people killed under the rubble. 

 

THE BERLIN FLAK TOWERS

The very first death of the civil population in Berlin brought to the common understanding the fact that Herman Goering’s empty promises that no bomb would ever fall on the territory of the Reich, had always been inadequate. As was stated above, in September 1940 Hitler ordered the creation of giant anti-aircraft towers for protection from, what the Germans called the ‘Terrorangriffen’ (terrorist attacks). The German word ‘Flaktürme’ is a short form for ‘Fliegerabwehrkanone’ or ‘aircraft defense cannon’. These monumental structures were meant not only to hit the enemy planes above the German capital but as an important political victory for the regime. Hitler regarded the project as a means to impress the Germans with the power of engineering genius of the Third Reich.  The flak towers also had a more practical purpose: to serve as air raid shelters for tens of thousands of people and the precious museum units and documents: an object of a larger concern for Hitler and the lives of children and women. 

The September sketches of Hitler drawing himself reflected his childish admiration of architecture and of monumental structures of the past. In his worldview, the flak towers would have to become the most massive fortified structures in the Third Reich at the moment. Hitler favored the Neo-Romantic style with references to medieval fortresses he had read so much about, yet the proposed size of the structures was a challenge in itself. While on paper the design of the new erections was the responsibility of Albert Speer, Hitler’s trusted architect, the actual design of the new construction was made by his subordinate since 1938 Friedrich Tamms (1904-1980), a professor at the Technical University of Berlin. The architectural concept of the towers was to be in harmony with the upcoming reshaping of Berlin, masterminded by the Nazi regime. Professor Tamms presented his first design to Speer as early as October 1940 which became a basis for the first complex towers in Tiergarten. The final detailed drawings and specifications were ready in March 1941 and Speer personally showed Tamm’s work to Hitler on April 20, Hitler’s birthday, when the Zoo (Tiergarten) flak towers were in the final stage of completion. Forasmuch as it had been decided to build the towers in pairs, Tamm’s designs included the vision of both the so-called ‘Gefechtstürm’ (G-Türm) or ‘G-tower’ (combat tower) and Leittürm (L-Türm) or ‘L-tower’ (control tower). The German fuhrer was impressed by the project and he wished the memorials boards devoted to German pilots to be added above every entrance to the combat tower. 

While it was initially discussed to build six pairs of towers, twelve erections in total, in later stages the number was restricted to three complexes. The three Berlin flak towers pairs were meant to be located in such a way as to form a kind of triangular for the protection of the central part of Berlin. At that time, Berlin was the third largest city in the world with its pre-war population of 4 321 000 people and covering 1400 km2. The Berlin flak towers were to become a part of a grandiose anti-aircraft defense system, divided into two large rings. The inner ‘flak’ ring of the anti-aircraft fire with a radius of 30 km from the city center, and the outer ring of searchlights of 45-50 km radius. In mid-January 1941 Speer finalized the location of the second complex in Friedrichshain park and finally on June 19, 1941, Humboldthain park in North Berlin was chosen for the third pair of flak towers. It is intriguing to note that in the same 1941 at least some officials proposed a plan to turn the four towers of Reichstag into anti-aircraft towers to improve the firepower of the anti-aircraft defense in the heart of Berlin. Such a peculiar project never evolved beyond talks and was probably rejected by Speer himself. 

It should be stated that the decision of building the flak towers in pairs was neither Hitler’s vision nor Speer’s decision, but rather a practical argument. In the hypothetical situation of placing both the heavy guns and radars in the same spot, the radar equipment was not expected to function efficiently. The anti-aircraft weaponry and the radar equipment were to be divided into separate installations with a distance of 300-400 meters, connected by an underground cable to transmit radar coordinates for fire. All three combat towers in Berlin were to be initially equipped with four pairs of twin 128mm Flakzwilling anti-aircraft guns, thus eight 128mm on each G-tower. The reality was that at the time of finishing the construction of all three complexes of the Berlin flak towers, this type of anti-aircraft gun was not yet put into full-scale production (second half of 1942). Instead of 128 mm, four single 105mm Flak guns were installed on each. The 128mm Flakzwilling 40/2 gun had impressive firing characteristics and would undoubtedly become the most effective anti-aircraft weapon of WWII. With a weight of 25 tonnes, it was capable of firing a shell weighing 26 kg at 14 800 m vertically and 20 900 m horizontally, with a kill zone of 240 m across. Considering the fact that the cannon demanded a substantial structure to withstand its 25-tonne recoil force, the massive Flak towers were a perfect place. An impressive vertical range of fire, up to 15 km, was aimed to force British aircraft to fly at high altitudes, which significantly decreased the accuracy of bombardment. The G-tower was also equipped with a 20mm and 37mm automatic cannon as a supplementary weapon for firing at lower altitudes.

With all its uniqueness and complexity in building, a necessity to find appropriate locations in the center of Berlin, all three complexes were finished in less than one and a half a year. The construction period of the ‘Zoo towers’ in Tiergarten lasted from October 1940 to April 1941, of the Friedrichshain complex from April 1941 to October 1941, and of the Humboldthain pair from October 1941 to April 1942, exactly six months for every pair. The first ‘Zoo’ complex was the most demanding of all, with up to 3200 of the workforce assigned at one time at the peak of the construction: the next two pairs would demand far fewer people and resources. Apart from Organization Todt’s involvement with prisoners of war as a working force, several respected German building companies also took part in the construction of the Berlin Flak towers. The contractors of the Zoo complex were later assigned to the two remaining pairs of towers. 

Philipp Holzmann AG founded in 1849, was one of the largest building companies in Germany and profited well in the years of Hitler’s regime. Since 1933 the company received numerous orders for construction projects, including Herman Goring’s mansion Carinhall, the New Reich Chancellery in Berlin, the unfinished Congress hall in Nuremberg, the road surface for the system of the autobahn, and the ‘Western wall’. Since the outbreak of WWII, Organization Todt has been the most profitable client. Despite its wartime activity, the use of prisoners of war and inmates of the concentration camps, and the after-war denazification, the company would later once again become the largest building company in Germany until its bankruptcy in 2002. 

Dyckerhoff & Widmann KG founded back in 1865, was another construction company, which used to get contracts from the Nazi regime. It moved its headquarters to Berlin in 1935 and during WWII as well used the working force from slave labor camps, including prisoners of Auschwitz. After the war, the company moved to Munich and resumed its operations. 

Habermann & Guckes AG founded in 1908, were experts in the extraction of gravel and the production of cement. In 1943 they would be also assigned to the construction of the bunker for the submarines at Kyll. After the war, the company moved to Hamburg in 1948 and worked until 1962. 

Gottlieb Tesch GmbH was founded back in 1876 in Berlin and soon became an influential provider in construction. In the late 1930s, the company got orders from the government, particularly cooperating with Deutsche Reichsbahn on the construction of the S-Bahn line in Berlin. 

Siemens Apparate und Maschinen GmbH established in 1933,  was a part of Siemens AG, tidily connected with the production of military equipment for the German army. The company was responsible for the installation of all of the technical and electrical equipment (including elevators, diesel generation sets, and ventilation) into the flak towers of all three complexes. 

 

FLAKTURM TOWERS IN HUMBOLDTHAIN

THE CONSTRUCTION OF THE COMPLEX

The final arrangements of choosing the location for the third pair of Berlin flak towers were agreed upon by Friedrich Tamms and Albert Speer as early as June 19, 1941, with the Zoo towers already finished (April 1941) and the Friedrichshain complex under construction (since April). The Humboldthain park was almost a perfect place for locating the two anti-aircraft giants here. Being located to the North of the city center, the park allowed it to complete the conventional triangular of air defense, at the same time being large enough to place two towers at a needed distance from each other. This construction would change the image of the park forever, actually destroying the delicate landscape vision of Gustav Meyer. The larger combat G-tower (G-turm) was to be located in the center of the Northern part of Humboldthain park at the arm’s end from the S-Bahn line, while the control tower (L-turm) was meant for construction on the site of the former rose garden next to Gustav-Meyer-Allee and the “Allgemeine-Electricitäts-Gesellschaft“ (AEG) facilities. Elegant walking alleys from the late XIX century were now replaced with practical pathways for military personnel. Above all, the digging of a giant trench between two towers for laying the cables devastated hundreds of rare trees. 

The construction of the Humboldthain flak towers was not as consuming in manpower as it was with the Zoo towers. In contrast to 3000+ workers on the construction of the first complex, the third one demanded the involvement of 800 workers between October 1941 and April 1942. 300 to 400 men in this workforce were Italian workers, who volunteered to work here and who gained a salary. The other part of the assigned workforce was recruited among the prisoners of war from France, Belgium, Holland, Yugoslavia, and the Soviet Union: they worked for food. In the winter months of 1941/1942, the labor force was accommodated at the small improvised Barack camp, carefully guarded in the center of the park between two towers, which once again was harmful to the Humboldthain appearance. In the same winter month, the local population became frequent visitors of the former favorite recreational area: they used the trees for heating during one of the coldest winters in decades. Later on during the war, the large open spaces were planted with potatoes and vegetables similar to the practice in the other parks of Berlin during WWII. 

In actual construction terms, the first component of the future giant G-tower in Humboldthain was the massive concrete founding known as “Schwerbelastungskorper” or “Heavy Load Body” of 12 650 tonnes and two meters thick, which had been worked out for the never finished GERMANIA project of remodeling Berlin. The construction process in the park was a 24-hour process and in the nighttime the building site was well-illuminated. The only reason for a break between October 1941 and April 1942 was the time of the night raids: the turn-off of the lights had become a signal for the people in the neighborhood a few minutes before the conventional radio announcement. A drill hole under the G-tower was meant to supply both towers with fresh water regardless of the Berlin water supply system. In the event of air raids, the complex was supplied by its own diesel engines with large storage of fuel enough for days of self-contained operation. Such self-inclusiveness of the Flak towers in Humboldthain park was also backed by a kitchen unit, a bakery, its own hospital, and even a separate premise for the local branch of the Gestapo, which supervised the security. The two towers were connected by a line of communication: communication, electricity, and even freshwater: all these laid inside trunking of 1.5 diameters dug in the ground under the park. While back in 1940 the rough estimates of the expenses for Hitler’s idea of the flak towers gave the figure of 24 million Marks for every pair, each of the three complexes massively overcame the budget. It is estimated that the Humboldthain towers’ expenses amounted to 90 million Marks. 

It is important to understand that it would take a significant amount of time between the finalization of the construction works in April 1942 and the first combat employment on January 17, 1943. A noteworthy detail is that the Berlin flak towers witnessed the visit of some high-ranking representatives of the Nazi regime such as of course, Reichsmarschall Hermann Goring, Albert Speer, and Joseph Goebbels. The Propaganda Minister particularly visited the Humboldthain complex in late 1942 and even posed for a photo on the site (unfortunately in too poor quality to show it here). As for Goebbels, we should keep in mind that he had been Gauleiter of Berlin since 1926 and would hold this post until his last breath on May 1, 1945. When it comes to Adolf Hitler, there are no confirmed facts that he ever visited any of the Berlin towers in Berlin, Hamburg, or Vienna. Anyway, he was to some extent excited about the construction and regularly discussed the progress with Albert Speer and even asked for photographs of the colossal structures. Speer himself had an experience of hiding in one of the Berlin towers during the air raid on November 22, 1943, while his own office was damaged. On that evening, 764 bombers of the R.A.F. attacked the Western part of Berlin, unleashing 2500 tons of bombs and killing not only citizens in their homes but also the animals of the Berlin Zoo. Every third creature in the zoo was killed, and numerous buildings were devastated, even the aquariums evaporated because of the extreme heat, leaving reptiles open to November cold and many of them died of hypothermia. 

 

THE DIMENSIONS OF THE HUMBOLDTHAIN TOWERS

The dimensions of the Humboldthain flak towers were not unique and reflected the overall design of professor Friedrich Tamms for all three complexes. The height of 39 meters for the combat G-tower was calculated based on the need to be higher than the surrounding buildings. The first reason for this was a necessity to have the maximum range of fire in all directions and the second to avoid the reflection of the sounds of flak gunfire, which could easily smash in the windows. The G-Tower foundation meas­ured 70.5 x 70.5 m. The thickness of the walls ranged from 2.5 meters of concrete for the lower floors and up to 2 meters in the upper part of the tower, reinforced with spiral metalwork. The roof was 3.5 m thick of reinforced concrete, estimated to stand against the direct hit of the heavy bombs. Later on, the towers of the 3rd generation in Vienna would have a lesser thickness of the walls: particularly 2 meters for the outer walls on the lower level and only 1 m at the upper levels. 

The control L-tower at Humboldthain had the same dimensions and specifications as its predecessors in Tiergarten and Friedrichshain parks. The shape was more rectangular with the sizes of 23 x 50 meters, thus making the area size 1150 m2 in comparison to 4970 of the G-tower. Despite the more moderate dimensions of the L-tower, it demanded 33,000 m3 of concrete. In fact, the erection of the L-turm in Humboldthain destroyed the ‘Rosengarten’ (rose garden), a favored place for the locals next to Gustav-Meyer-Allee. It is worth a remark that the control tower in Humboldthain had slight architectural differences when compared to the first two complexes: parapets for low-caliber flak guns. The L-tower had an aviation armament laboratory for the staff of the ‘Telefunken’ company, founded in Berlin in 1903 as a joint venture of Siemens and AEG (the company, whose facilities were located to the south of Humboldthain park). During WWII Telefunken, absorbed by AEG completely in 1941, was the leading German company in the field of electronic warfare and provided radars and electronics for the Luftwaffe. This laboratory studied the hit Allied aircraft and provided the German army with recommendations regarding the response procedures during the upcoming raids as well as means to improve German radar systems.

 

 

THE STAFF AND COMBAT STANDBY DUTY

When it comes to the structure of command, the German air defense forces had their own composition with decentralized command. Large formations (divisions and brigades) were subordinate to the local Luftwaffe commandership, thus dividing the territory of the Third Reich during the war into ‘Luftgau’ (air defense districts). Such an approach of managing all the flak units in the region allowed a flexible organization. The division was divided into ‘Flak Gruppen’ (air defense groups) equivalent to regiments in the army. In one turn, these groups were subdivided into ‘Untergruppen’ (sub-groups) equivalent to a battalion and the basic anti-aircraft formation in Luftwaffe was the ‘Batterie’ (battery). Initially, in 1942, around 160 soldiers under six officers were assigned to serve as a battery inside the Humboldthain G-tower (combat tower) and another 100 with six officers at the L-tower: approximately 270 in total for the complex. As the war progressed, the initially assigned staff was augmented by young and non-pro soldiers without combat experience known as ‘Luftwaffenhelfer’ or simply  ‘LH’, female helpers known as ‘Blitz Madchen’ (the lightning girls) and even by foreign auxiliaries among the former Soviet pows. 

The ‘Luftwaffenhelfer’ (Luftwaffe assistant) was adopted in Germany due to the lack of military personnel three and a half years after the outbreak of WWII. This formation was formally created by the decree called ‘Krieg hilfseinsatz der Jugend Bei der Luftwaffe’ which may be translated as the ‘War auxiliary deployment of youth into the Luftwaffe’ or ‘War aid mission of the youth in the air force’. The program decreed on January 22, 1943, was intended to prepare young men and later girls for the service in the German air force. The draftees were male school students born in 1926/1927, assigned to help the Luftwaffe under the supervision both of the army and the ‘Hitler Youth’ movement. In early 1945 the conscription would be extended to young men born in 1928/1929. The first group of eighteen boys from the Berlin theological school was assigned to perform service at the G-tower at Humboldthain as early as February 15, 1943, less than a month since the initiation of the ‘Luftwaffenhelfer’ program. Worth noting is that the boys had not graduated yet and apart from their military service for the Reich, they had to continue studying, in parallel to the flak service and the obligation to visit the ideological call in Hitler-Jugend. As instead of ‘Luftwaffenhelfer’, “Flakhelfer” (Flak-assistant) was of common use, the boys of these units born in 1926/1927 were later attributed as the “Flakhelfer-Generation” (generation of flak assistants). 

‘Blitz Madchen’ (the lightning girls) were young German women, mainly from ‘Bund Deutscher Mädel’ (BDM), a female branch of the Hitler Youth. Since the outbreak of the war in 1939, BDM members were involved in military operations as hospital aids, air raids, and land helpers and in many other ways outside of military service. When it came to the service at the flak towers, these girls were mainly assigned to help in the operation of the radio equipment and passing the air messages and reports. As a lightning bolt was the sign of the communication troops, at some point the troops started to refer to those girls as the “Blitz Mädchen” or ‘Blitzmädel’, where ‘madel’ is translated as a young woman. In regard to the foreign volunteers, toward mid-1944 the lack of military personnel would become disastrous. Initially, the natives of Chezh Moravia agreed to serve in the flak forces, and later the former Soviet POWs agreed to serve for the purpose of the Third Reich. For obvious reasons they were applied to the inferior assignments inside the flak towers as an unqualified workforce in the kitchen, laundry, and sometimes as electricians and repair workers. 

While the primary construction process of the Humboldthain flak towers was finished as early as April 1942, the complex was put on full combat alert only in January 1943, with the first combat employment on January 17, 1943. As I have stated above, initially the G-tower was not equipped with 128 mm guns. In the period from January to August 1943, the gun crews of the Humboldthain G-tower used four 105 mm Flak guns as a primary weapon and 37mm and 20 mm guns as supplementary. The August 1943 augmentation with the 128 mm guns was not the last. As early as 1944 the 37mm Flak 18 was replaced by the Flak 43 model of the same caliber. This model proved itself to be defective (the shells used to blast inside the gun frequently) and in early 1945 they were replaced by 50 mm Flak 41 guns. The preserved Luftwaffe records of the anti-aircraft combat activity in Berlin give us the ground to try to evaluate the efficiency of the Humboldthain flak complex. Between January 1943 and May 1944, this pair of flak towers managed to succeed in eleven confirmed hits against the Allied aircraft, and toward the end of the War in May 1945, it had 32 confirmed hits. The result was possible due to the skillful cooperation between the firing G-tower and the radar personnel at the control L-tower. The soldiers used to paint white rings on the barrels of the guns denoting hit aircraft. It is interesting to note that until mid-1944 there were four wooden towers in the neighboring area with a 600 mm ‘Flakscheinwerfer’ Flak-Sw 36 searchlight on each, but the operational efficiency was only 3600 meters, which proved insufficient against high bombers. In 1943 an American pilot managed to land with his parachute right on the L-tower after his plane had been hit. As for the killed crews of the Allied bombers during multiple raids over Berlin, they were mainly buried at the Commonwealth War Cemetery on Heerestrasse 139 in West Berlin. 

When it comes to the damage to the towers in the years prior to the Battle of Berlin in 1945, both Humboldthain flak towers got relatively insignificant harm. Since being put on combat standby duty in January 1943, the combat G-tower witnessed three hits, with the heaviest on March 18, 1945. On that day Berlin suffered a massive air raid by the American Eighth Air Force. After the air raid alarm at 11 a.m., the attacking bomber squadrons came from the west and southwest and badly hit the city center, including the area of Humboldthain park. The G-tower suffered two direct hits of the air bombs, probably US M43 HE Bombs weighing 225 kg each. Two crews of the 128 mm guns suffered the loss of a total of seven dead and at least twenty severely wounded soldiers and officers. A young ‘Flakhelfer’ Horst Hirche, who lost his left eye, would later reveal his recollections about the raid and his service at the Humboldthain flak tower, a precious first-hand testimony. Two 128 mm guns, regarded as ‘Dora’ and ‘Anton’ were knocked out to be later repaired in the final stage of the war. The G-tower itself showed no significant structural damage and the hit of the 225 kg bombs resulted in no cracks in the ceiling or walls. 

With regard to the damages to the L-tower, it suffered one profound hit from a heavy air bomb on November 22, 1943. On the one hand, the damage was sizable: one of the 105 mm guns was blasted over 400 meters away in the direction of the AEG facilities to the South. The explosion on the roof resulted in the crack of concrete and some rainwater later flowed into the room on the upper floor of the tower. On the other hand, there were no casualties in the accident as the flak crew had been ordered by its officer to take cover inside the tower a few minutes before the raid. 

 

AS A RAID SHELTER AND A STORAGE

It was Hitler who back in September 1940 determined several purposes of the Flak towers in Berlin. Apart from the defense of the sky over the capital from enemy aircraft, the designs professor Tamms included the large premises for civilians and the air raid shelters of great capacity. Modern WWII historiography debates over several figures of how many people could the Humboldthain G-tower take in during the air raids. The lowest and the most frequently mentioned figure is 8000, and it was the number of civilians who could find safety inside the tower during the air bombardment of Berlin. The frequent estimates of 16 000, 21 000, and even 40 000 are the suppositions of how many people were in fact crumpled into the G-tower. The point is this figure was not limited and strongly depended on the occasion, the intensity, and the time of the air raid. The more time bombardment lasted and the more severe it was, the more people took shelter inside the flak tower of Humboldthain. There is also a dispute that there were passages between the G-tower and the neighboring Gesundbrunnen S-Bahn train station, which lack factual proof. The highest figure of 40 000 civilians in fact supposes the overall number of people both in the tower and in the metro underground system nearby: two figures which should be discussed separately. As far back as 1935 the air-protection system, including the air conditioning, was installed in the basement of the building of the Gesundbrunnen underground station, yet there was no connection with the flak tower. Unfortunately, there is no information preserved about the capacity of the people the control L-tower could accommodate. 

It is worth noting that you may come across several different numbers of floors for the G-tower: in fact, there is no mistake and it will depend on the fact whether one or another source includes the basement and the ground floor, leaving five floors above the ground. In general terms, the Humboldthain combat tower was large not to say giant structure with a myriad of premises, hoistways, and entrances. It would be incorrect to regard it as a giant concrete rectangular box with guns on the roof. The quartering facilities under the ground level were used as artillery casemates for reserve gun barrels, shells for main guns (105mm and later 128mm), and repair machinery and accessories. In the late stages of the war in 1945 the civilian population was taken to the basement floor as well. Getting back to the estimate of people the G-tower could take, the first floor above the ground among the five was designed to welcome up to 8000 people, apart from all other parts of the tower. The first floor also had three main entrances equipped not only for people but large enough for the lorries. 

The second above the ground floor of the Humboldthain G-tower facilitated the military hospital, which was also used to help wounded civilians during the air raids. In the advanced stages of the war with the intensifying of the air raids against Berlin, particularly in 1945, there was a maternity ward, an improvised branch of the Berlin hospital. Dozens of children were born inside the Humboldthain complex during the war. When it came to the third floor, at some stage it was prepared and equipped with its own ventilation spur as storage for the museum units. Initially, Adolf Hitler put greater attention to the preservation of the arts than to the defense of the lives of civilians during the air raids. There is no precise information about the relics inside the Humboldthain tower, but the Zoo flak tower in Tiergarten was used to store the so-called ‘Priam’s treasure’, which had been discovered by Heinrich Schliemann on the supposed ruins of ancient Troy In the XIX century, to be in 1945 stolen by the Soviets. The fourth floor was for the military staff only. It included the kasernes for the office staff and soldiers, facilities for receiving and operating the control data from the L-tower, and meeting rooms. The last fifth overground floor was in fact a massive additional superstructure above the main quadrate body of the tower. It was used as munition storage for guns of smaller caliber (20 and 37 mm, later 50 mm), and facilities for cover. The G-tower was serviced by two elevators with a capacity to take up to twenty men at once with the ability to deliver tonnes of artillery shells and heavy barrels, evacuate those wounded, and move museum pieces. A powerful diesel engine and two reserve petrol-diesel units were installed for the needs of both Humboldthain anti-aircraft towers. 

 

THE TOWERS DURING THE BATTLE FOR BERLIN

Toward April 1945 Berlin turned out to be a giant deadly trap for almost 3 million people, both civilians, and military men. The heavy air bombardments of the city resulted in the collapse of the civil infrastructure, particularly of the water-distribution system, which made people wait in lines for water for hours during the continuous air raids. It comes as no surprise that in the last weeks of the war, almost every air raid shelter in Berlin, especially those of large capacity, was crammed with people. The Humboldthain complex was not the exception. The civilian population was to find here not only a cover from the heavy bombs and street fighting in late April – early May, but they got access to some food and particularly fresh water, which was supplied from the drill hole under the G-tower. In the crowded premises without daylight, there was no basic hygiene and suicide became a frequent reality: women, particularly among the ‘Blitzmadche’ personnel jumped into the stairwells to kill themselves. Apart from thousands of scared people, the hospital could not anymore handle all the wounded, who were brought to the tower for medical help and cover. Every shot fired from the tower, as well as the enemy fire against it, shook the structure with a thunderous sound echoing through the building. The crying of people and the last breath of those dying were mixed with the rattling of automatic elevators, which were used to get ammunition from the ground floor to the roof. The cacophony of noise was sometimes intolerable. 

The Soviet advance toward Berlin, initiated on April 16, resulted in the encirclement of the city as early as April 25 and the streets were now a place from Dante’s ‘Inferno’ with a fight for every corner and street despite the inadequate correlation of military capabilities of the defenders and the invaders. In those last days of the Third Reich, all six flak towers in Berlin, especially the G-towers, became an integral component of the city defense, which caused the Red army heavy losses and difficulties. During this period they were not used for air defense, but primarily as the strongholds of the resistance, heavily defended and protected by meters of concrete. The soviet archives later revealed the agony-like reports of the combat troops in pursuit to take the towers. They found it impossible to cause significant damage to any of the six towers, including the G-tower in Humboldthain. The units of the Soviet 12th Guard corps systematically shelled the G-tower with T-34 tanks and heavy 203 mm howitzers, which brought no sizable result. They grabbed surviving civilians on the neighboring streets to force them to drag the long-barrelled guns into position to fire at the towers in Humboldthain park against their German counterparts, family members, and friends. Soviets also sent infantry units and even put snipers on the roofs of the burned buildings nearby to suppress the fire. The defenders of the G-tower, stocked with plenty of ammunition, used their low caliber 20mm guns to fire at the ground units. All these made the attackers bypass the towers for some time and attack or destroy them once the other parts of the city were taken. 

It is important to understand that apart from the flak units of the tower among the Luftwaffe, the Humboldthain park was also fought by the remnants of the Wehrmacht units. By taking advantage of the temporary retreat of the Soviet forces from the park, on May 2 up to a thousand German soldiers made an attempt to break through the enemy lines in the North direction. General Erich Bärenfanger was the highest-ranking officer among this mass of people. A week before he was promoted to major general bypassing the rank of colonel which made him the youngest general in the German army: Bärenfanger was only thirty. In the last days of the Battle for Berlin, he was appointed the commander of the so-called defense sectors A and B. On that day of May 2, Bärenfanger allowed the soldiers to make the arms unusable for enemies and to try to make a breakthrough in the north direction of Oranienburg in small groups to avoid Soviet captivity. Some of these men indeed managed to escape the city. General Erich Bärenfanger was not successful in breaking through and committed suicide with his wife and brother-in-law in the brewery only 2 kilometers from Humboldthain park. The tower commander Oberleutnant Meyer succeeded to make his way out of the city days before capitulation and reached the US forces on the Elbe when his subordinates were still dying defending Berlin. Finally, the remaining defenders of the G-tower surrendered at noon on May 3, 1945, just before another Soviet attempt to destroy the tower with the explosion. After the Red army officers left the structure, a group of half-drunk soviet soldiers penetrated the tower and started robbing people inside, including those wounded. All the men in the tower, mainly elderly, invalids, wounded and boys, were then taken as prisoners and the invaders took over the control of the structure as a temporary command post. 

 

HUMBOLDTHAIN TOWERS AND PARK AFTER THE WAR

The fight for Humboldthain park was demandable in human resources for the invaders with the heavy price of victory. On June 5, 1945, the ‘Berlin declaration’ (Berliner Erklärung) was signed, which finally anchored the previously taken decisions (The February 1945 Yalta conference) to divide the conquered Germany into four occupational zones: American, British, French, and Soviet. Later on August 1, the takeaways of the ‘Potsdam conference’ confirmed the newly created boundaries in Europe and particularly in Berlin. According to the new borders, the Wedding district and particularly Humboldthain park was now a part of the French sector. As early as December 6, 1945 decree No. 22 of the newly-established ‘Allied Control Council’ established justification for destroying multiple military buildings and erections as a part of the demilitarization process in Germany. The six former flak towers (the Zoo towers in the British zone, Frie­drichshain flaktürme under the Soviets, and Humboldthain in the French zone) were given the highest priority for demolition as the ‘heavy battle structures’ and symbols of the former Nazi regime. The carrying out of decision was to become a kind of post-war competition between the former Allies. 

After the Soviet soldiers left Humboldthain park and the Wedding neighborhood, the French administration used the towers as warehouses, and workshops. While the British completely destroyed their Zoo towers in the summer of 1947 and the Soviets devastated the pair at Frie­drichshain flaktürme already in 1946, the French were the last to stand against the former giants. The first attempt to destroy the G-tower was carried out on 25 October 1947 and it resulted less in the aim than in blasting the windows of the buildings in the neighborhood, which had previously survived the Battle of Berlin. On December 13, 1947, they were more successful with the blowing up of the smaller control tower with 16 tonnes of explosives. At the beginning of 1948, the larger G-tower was still mostly unharmed and another two attempts were carried out. The second explosion was set up on February 28, which still did not cause the tower to collapse. The third and final explosion on March 13 took advantage of the 25 tonnes of explosives and the southern part of the G-tower collapsed. There are a few reasons why the French did not proceed with the demolition. The ‘official’ version stated the danger for the neighboring area with the further explosions. A more practical explanation can be found in the S-Bahn line to the North, which at that time was already in the Soviet zone and the blasting of the tower could cause damage to the infrastructure. Even more practical reason was the lack of desire to neither spend time and resources nor face the possible fourth failure in contrast to the relatively successful operation of that kind by the British and Soviets. 

 

TWO HILLS OF RUBBLES AND THE PARK

With the end of the Battle of Berlin, the greater part of the city lay in ruins or was heavily damaged, especially the city center. According to the most accurate post-war estimates, between 12 and 20 % of the buildings in the city were irreparably destroyed and up to 75% severely damaged, leaving in total up to 50 million cubic meters of ruins (one estimate suggests as much as 75) which were to be handled in one way or another. The central part of Berlin was left with only 18 000 buildings among the pre-war 150 000 suitable for use, with another 32 000 completely destroyed. Among the 1.5 mln apartments, 730 000 were still inhabited. Speaking about the enormous amount of rubbles, three central districts of Mitte (78% of irreparable destruction), Tiergarten (48%), and Friedrichshain accumulated a total of 20 million cubic meters of ruins, leaving 6 mln to Schöneberg, 5.8 mln in Steglitz, 5 mln in Kreuzberg, 4.1 in Tempelhof. The amount of rubble in the other districts, including Wedding, varied up to 4 million. The removal of ruins in Berlin started as early as May 3, 1945, and lasted until 1957. The peaks of the ‘clearing the debris in the first post-war years saw up to 35 000 people assigned at one time with up to 800 lorries of rubble daily. The greater proportion of work, around 75% was carried out by women and in most cases, such hard work was the only legal way to get ration cards for food. Approximately two-thirds of the material was intended for reuse and the ruins unsuitable had to be disposed of at suitable locations in Berlin or outside the city. To speed up the process narrow-gauge railway lines were laid out to transport the rubble over distance. The steady process allowed for a decrease in the unprecedentedly high level of air pollution in the city after the war. 

As the process of clearing debris progressed in all four occupation zones, it was decided to create ‘rubble dumps’ which were intended to be remodeled for public use. Humboldthain park was among the fourteen such large dumps with the ambition to create a new public area. While the reshaping of the Frie­drichshain was put into practice as early as 1946, Humboldthain was left for some time in waiting for a new development plan for the park, which was finally ready in October 1948. In general means, the process of delivering hundreds of thousands of tonnes of rubble here was in parallel with the post-war recovery of the Humboldthain park, supervised by Fritz Witte (1900-1972), the head of the newly created ‘Main Department of Green Space and Horticulture Landscape Gardening’. As early as August 22, 1949, the ‘Urban Planning Law’ of Berlin was signed, which included the renovation of Humboldthain park. The leveling up and filling with the debris of the former L-tower was finished in July 1950. The larger bunker was a more difficult task as it was not completely destroyed in either of the attempts. Toward September 1950 up to 900 men and women were working here at once, using horse carriages and railway lines and it demanded 1 million tonnes of rubles to cover the remains of the G-tower, with the total amount of 1.6 million for two hills in Humboldthain until the cessation of works in 1951. During this period a significant amount of steel construction of the former tower was taken for reuse due to the severe shortages of the material in post-war Berlin. 

When three years of hard work came to an end, the ruins of the two Humboldthain flak towers were fitted into the new landscape of the park. Apart from the ‘demilitarization’ of the constructions and serving as a rubble dump, the new hills were to serve a garden-architectural purpose. As a result, the height of the hill above the former combat tower is 85 meters above sea level, and 68 meters above the former L-tower, in contrast to 87 and 57 respectively in Frie­drichshain. The hill of the larger partially destroyed tower in Humboldthain known as ‘Bunkerberg’ (bunker mountain) was created with a circular serpentine path with a slight incline to make it accessible. The lower hill also received its own path system but there are only rare remains of the former control tower. After covering the hills with 30 cm of a thick layer of topsoil, the greening was carried out. As the idea was to green the area in a short period of time, the fast-growing trees such as maples, oaks and beeches, poplars, robinias, and the bushes of wild roses were planted. The more practical reason for the speeded-up greening was to make the roots system of the plants to prevent the erosion of the soil. Toward 1952 up to 60 000 trees and bushes were planted in Humboldthain park, in contrast to thirty trees still standing in May 1945. Garden director Günther Rieck was responsible for the process. 

The burn-out ruins of the ‘Himmelfahrtkirche’ (Ascension Church) which are recognizable next to the G-tower in the post-war photos, were also leveled up and used as rubble for reshaping the park, after the final blown up on July 14, 1949. Later a magnificent rose garden was created on the exact site of the former church facing Brunnenstraße in the Eastern part of Humboldthain park. The total estimated cost of reconstruction of the park was 4 million marks, which came from both the investors and the ‘Marshall plan’ aimed at rebuilding Germany. If we consider the total number of plants planted over the decades, the figure may reach 200 000, including 16 000 in the rose garden alone. The open space in the center of the park was to make a contrast to the densely planted hills and the outdoor pool became a desired place of leisure for the local people. The new ‘Volkspark Humboldthain’ was opened on September 13, 1952, as a new recreational area with the memorial stone devoted to Alexander von Humboldt at the foot of the small bunker hill in its southern part. By the end of 1955 around DM 93 million had been invested in green measures in Berlin. Among other things, 2,350 ha of recreational areas were restored or newly created. This was particularly important because the division of the city meant that many Berliners had less access to leisure and recreation facilities.

The post-war history of the former G-tower in Humboldthain was not finished with the reconstruction of the park and the creation of the hill.  The new height was incorporated into the local landscape to become a viewpoint, planned with trees with access to the top by means of two pathways. The first one with a rapid ascent made of 160 steps and the second one is much more accessible with a spiral-kind footpath. For obvious reasons, there was no possibility to make the ruins of the tower completely safe. The site witnessed several earth tilling accidents and the collapse of some rubbles and as early as 1955 the local people appealed to the authorities to take safety measures. The hill became dangerous for walking, first of all for children and even for homeless persons, who had used to find cover inside the wreckage. It was not a question of complete demolishing, yet the entrances were bricked up. It is interesting to note that back in the 1950s the former northern wall of the tower facing the S-Bahn was favored by the climbers of the Alpine Association’s Berlin Section. Seventy years later, at present, the wall is still one of the favorite locations for climbers in Berlin. There is an informational plaque in German, that states that the Alpine Association accepts no responsibility for possible accidents and that children should be treated with a double attitude. 1967 witnessed the erection of the sculpture which would later play its role in the preservation of the remnants of the tower. The monument known as ‘Reunification’ was installed on the site on August 13, 1967. The date was not accidental as it reflected the sixth anniversary of the sadly remembered erection of the Berlin wall, which had divided Berlin for decades. Thus, the sculpture by the artist Arnold Schatz was meant to symbolize a dream for the future reunification of Germany and the city: plans, which were still twenty-two years ahead. The eleven-meter-high aluminum sculpture stands on a walled concrete base and consists of two steel-like metal parts that are surrounded and held together by a ring. On October 2, 1991, the mayor of the then district of Berlin-Wedding, Jörg-Otto Spiller, would unveil a bronze commemorative plaque on the concrete base of the memorial. It bears the inscription: “Memorial of the unity of Germany, 13.8.67. Arnold Schatz”.

With consideration of the critical condition of some parts of the former tower, the disputes regarding the complete demolition were a public debate between the mid-1950s and reached its peak in 1986. In that year the rough estimate showed the potential expenses of 20 million Deutschmarks for the complete reshaping of the hill and it was decided to spend a significantly smaller sum to turn it into a memorial. The Northern wall 15 in height and its use by the climbers became one of the preserving factors, as well as the favored sculpture by Arnold Schatz. The new reconstruction took two years and a new viewing point was opened in October 1990 at a total cost of 3 million marks, seven times less than the estimated expenses for demolition. The existing halls were closed with concrete, the walls with the remains of the WWII shelling were smoothed and two and a half meter-high steel fence was erected to avoid both accidents and suicides. As early as 1995 the Volkspark Humboldthain became a monument of Berlin. 

In the new millennium, the former Flak tower in Humboldthain got its third wind of public interest. In 2001 the Berlin Underground Association conducted an expedition inside the formerly sealed remains of the G-tower. This event had not only cognitive but also informational meaning. While the authentic designs of the tower had not been preserved and for years the researchers lied on the similarity of the Humboldthain complex to another two pairs of flak towers, the expedition revealed differences in the layout of rooms. They even reached the basement level. Two years later in 2003, the Berlin Underworlds Association initiated ambitious works on clearing the inner premises of the upper levels, which resulted in extracting more than 1400 cubic meters of rubble. Since April 2004 any enthusiast may get into the two upper levels of the tower in the format of group tours. It is interesting to note that the site is accessible to tourists in the period from April to October so as not to disturb thousands of bats, who spend their winter months in the depth of the tower. When I visited the site in September 2019, I met a tourist group just during their tour.