The Flakturm (flak tower) Friedrichshain was built from April to September/October 1941 as a part of the Berlin air raid protection system. It consisted of two flak towers: a bigger G-Turm (cannon tower) for the heavy anti-aircraft guns and a smaller L-Turm (command tower). The bunkers also served as an air raid shelter for the local residents, of which around 50,000 found refuge inside the towers. Additionally, the L-Turm served as a storage for the art pieces of the Berlin art galleries. The recruited combat personnel were mostly teenagers between the ages of 16 and 18, who served as Luftwaffe assistants and replaced adults, who served at the front. Women and prisoners of war also belonged to the assisting personnel. During the Battle of Berlin, the towers and their defenders played a key role in defending the area by giving supporting fire with their heavy flak cannons.

Therefore, the units of the Soviet 7th Rifle Corps were involved in heavy fighting, which lasted from 25 April until 2 May 1945 and slowed the Red Army’s advance around the Friedrichshain Park considerably. A few days after the defeat of the Berlin garrison, on 6 May, the L-Turm was set on fire, leaving approximately 434 paintings from the Berlin Painting Gallery destroyed. Some of the statues, which were also stored there, were discovered in Moscow in 2016.

The Red Army attempted to demolish the bunkers with explosives in May 1946 but were only partly successful, so that the damaged bunkers were later shovelled over to form two hills, the Großer Bunkerberg (Big Bunker Mountain) and the Kleiner Bunkerberg (Small Bunker Mountain). Later on, the large hill was nicknamed Mont Klamott (Rubble Mountain) and served as an inspiration for several East German songs.