Flak Towers in Berlin

The Pairs at a Glance

The table compares the three Berlin flak tower pairs: when each was built, what happened to it after 1945 and what a visitor sees at the site today. The figures come from the historical sources listed below. Each pair consisted of a G-tower (gun tower) and an L-tower (control tower) working together, and the fates of the three pairs differ sharply.

The Zoo pair was blown up completely, the Friedrichshain pair was buried under rubble mounds, and the Humboldthain pair was only partly demolished, which is why its northern section survives as a walkable ruin.

The Zoo Pair

The Zoo gun tower, named Gustav, was finished in April 1941. The control tower was built in 1939-1941 across the Landwehrkanal in the Tiergarten. During an alarm the Zoo tower sheltered up to 16,000 civilians, and the headquarters of the 1st Flak Division under Generalmajor Otto Sydow sat inside the Zoo bunker.

Hermann Göring stayed briefly in the Zoo bunker hospital in April 1945. The bunker also stored Schliemann's 8,900-piece Priam's Treasure, which a Soviet trophy commission seized in May 1945. Moscow's Pushkin Museum revealed only in 1994 that it held the treasure.

Both towers fell in the British sector. The control tower was blown up on 28 July 1947 with 12 tonnes of dynamite, and the gun tower was finally destroyed on 30 July 1948 with 40 tonnes of TNT. Sources differ on whether the gun tower fell in 1947 or 1948.

Sources differ on whether the gun tower fell in 1947 or 1948. Nothing stands today.

The Friedrichshain Pair

The Friedrichshain towers were finished in October 1941. Over 700 square metres of Berlin Picture Gallery paintings were stored in the smaller control tower, and about 434 of those paintings burned there, probably on 6 May 1945, in circumstances never explained. The Red Army blew the towers up in May 1946 with only partial success, so the remains were turned into hills.

Two rubble mounds, the Großer and Kleiner Bunkerberg, now shape Volkspark Friedrichshain. The Friedrichshain mound carries the nickname Mont Klamott. An observation platform stands on the remains of the combat tower atop the Großer Bunkerberg, which lets you stand on flak tower concrete.

The Humboldthain Pair

The Humboldthain tower was built from October 1941 to April 1942 using many forced labourers. After the war the demolition teams could not destroy it fully, because the Ringbahn railway line beside the park could not be damaged. That accident of geography is the reason Berlin has a flak tower ruin at all.

The northern section of the bunker stays visible above the park and can be entered on a Berliner Unterwelten tour, the only way inside. The park is reached from S+U Gesundbrunnen station, which also has the association's shelter under the station used on its other bunker tour.

The G-Tower and the L-Tower

Every pair consisted of a G-tower, the gun tower that carried the anti-aircraft batteries, and an L-tower, the control tower that aimed them. A first-generation G-tower measured 70.5 metres square and about 39 metres tall, with concrete walls up to 3.5 metres thick. A first-generation G-tower mounted eight 128 mm FlaK 40 guns.

Speed of construction was extraordinary: all three Berlin gun towers went up within six months, and national rail schedules were altered to deliver materials. As concrete shelters and vaults they protected people and stored property.

Shelter and Storage

The Zoo tower sheltered up to 16,000 civilians during an alarm, a figure that shows the scale of the interior. Storage mattered as much as shelter. The Zoo bunker held Schliemann's 8,900-piece Priam's Treasure until a Soviet trophy commission seized it in May 1945.

The Friedrichshain control tower held over 700 square metres of Berlin Picture Gallery paintings, of which about 434 burned in May 1945 in unexplained circumstances. The fate of the art is a reminder that the towers were instruments of a total war that destroyed cultural heritage as well as lives, and that some losses remain unsolved.

The Ruin and the Park

The northern section of the Humboldthain bunker rises out of the park and is freely visible from the paths. The park is reached from S+U Gesundbrunnen station. The Berliner Unterwelten meeting point for the flak tower tour is the lower platform of the ruins in Volkspark Humboldthain.

Prices for a comparison: a BVG single AB ticket for the ride to Gesundbrunnen costs €4 (reduced €2.50), a short trip ticket €2.80, and the flak tower tour itself €17 (reduced €13) per the 2025 flyer. The Humboldthain ruin is the only flak tower in Berlin that can still be entered, and its bulk gives a sense of the concrete the wartime crews worked behind.

The Flak Tower Tour

The flak tower tour (From Flak Towers to Mountains of Debris), enters the Humboldthain ruin. It is only for people aged 18 and over and requires sturdy closed shoes. The 2025 flyer gives 90 minutes and €17 (reduced €13), the same fare as Tours 1, 3 and F. It describes the three pairs of flak towers intended to defend Berlin and shows remains of three of the original seven floors.

Tickets are sold only through the online shop tickets.berliner-unterwelten.de, with no sales at the meeting point, and you can book up to 30 days ahead. Photography and filming are forbidden. There are several staircases, no chairs and no toilets, large luggage and prams are not allowed, and the buildings are not suitable for disabled visitors.

Tickets cannot be exchanged or cancelled, though unnamed tickets may be passed on.

Seeing the Tower by Bike

If you cannot join the 18-plus underground tour, the exterior is easy to reach by bicycle. The listing for the Wall and Third Reich bike tour names Flak Tower III in Humboldthain among its stops, so riders reach the ruin on a 3-hour, 15-kilometre route that costs $39 and includes the bike, a helmet on request and rain ponchos. The group meets at Poststrasse 11.

Routes vary by guide. For everything else underground, from the Gesundbrunnen shelter to escape tunnels, see the guide to Berlin underground tours.

What Else Is Nearby

Gesundbrunnen also hosts Berliner Unterwelten's exhibition 'Hitler's plans for Berlin: Myth of Germania' at U Gesundbrunnen, open Saturdays 11:00-17:00, admission €6 (reduced €5) per the 2025 flyer. If you want bunker interiors without the age limit, the Berlin Story Bunker entry ticket near Anhalter Bahnhof covers a real WW2 air-raid shelter for $20, and the Berlin Wall and Third Reich Guided Bike Tour adds the Boros Bunker and the Wall Memorial on Bernauer Strasse to the Humboldthain pass. Comparison of tour prices, in dollars exactly as listed: the bike tour $39, the bunker ticket $20, the two-hour walking tour $27 and the historian-led small-group walk $51.