On the 10th of September 1940, as a result of a personal order from Hitler, the construction of so-called “Flakturme” (anti aircraft towers) began, which were intended to protect the city centre of Berlin from aerial bombardment. The first two towers were built in the Tiergarten and Friedrichshain parks – the third in the Humboldthain park was built between October 1941 and April 1942. The Flak bunkers towered over their surroundings. The anti-aircraft cannons were aimed with the help of an additional tower, a so-called “Leitturm” (control tower), whose ruins still protrude from the rubble mountain on Gustav-Meyer-Allee. Inside the Flak tower, which was considered at the time to be completely bomb-proof, there was also space for 15.000 civilians.
After the war, the Berlin Flak towers were blown up as military structures. The north side of the Humboldthain Flak tower, which was blown up by French pioneers in 1948, remains only as a ruin. After the detonations, over 1.5 million cubic metres of rubble was piled up on top of the remains creating a “mountain of debris”.
After more than 50 years, the Berlin Underworlds Association has been able to make the ruins accessible. After thousands of hours of work we were to celebrate with a topping-out ceremony on the 18th of October 2003. The then district mayor for Mitte, Joachim Zeller was present, along with the parks and gardens department and other friends and supporters of the association. Since April 2004 the tower has been open for visitors.