Zoo flak tower The Zoo flak tower , ( German : " Flakturm Tiergarten " or the " Zoo Bunker " ) , was a fortified flak tower that existed in Berlin from 1941 to 1947 . It was one of several flak towers that protected Berlin from Allied bomber raids . Its primary role was to protect the government building district of Berlin , as well as provide bunker space for civilians during attack . The Zoo tower also had a hospital facility . Apart from its primary designated role , the Zoo tower also provided storage facilities for art treasures to safeguard them from damage , and broadcast radio transmissions from the German leaders . During the Battle of Berlin , it acted as a citadel and provided support for ground operations by German troops in combat with Soviet ground forces . Development . The Berlin flak towers ( " Flak Schturm " ) were originally built as a response to an attack on Berlin by a relatively small force of British bombers . Hitler ordered the construction of these towers after the first bomber attack on Berlin by the RAF on 25 August 1940 . Although only 95 RAF bombers constituted the attack force , this was a grave domestic political embarrassment to Adolf Hitler , and in particular Hermann Göring , who had said that Berlin would never be bombed . The Zoo tower was built close to the Berlin Zoo , hence the name , and is the most famous of the flak towers . It was the first one built and protected the government quarter in Berlin . Layout . The Zoo tower was a first generation flak tower . Like all the flak towers , it had a main facility that housed the anti aircraft guns , the G building , and a smaller building that had sensory equipment , including radar . This was the smaller L building . The two were connected by a landline that was buried in the ground and protected . There was one cellar floor and six upper floors above that , though the tower rose to roughly the height of a 13 - story building . The second floor was used to house the most priceless and irreplaceable holdings of 14 museums from Berlin . The rooms were climate controlled . On the third floor was an 85 - bed hospital . Specifications . As with all flak towers , the installation consisted of two towers , the Main G tower , which held the anti aircraft armaments , and the L tower which held radar and detection equipment . The G Tower could accommodate 15 , 000 people . The Main G tower was crewed by 350 Anti aircraft personnel , and assisted by Hitler Youth . It was a ferro - concrete structure the larger tower was an extreme structure , roughly 70 meters wide by 70 meters long . The walls were 8 meters thick , and the roof was 5 meters thick . It was the largest air raid shelter in Berlin . In terms of provisions , and the defenses of the Zoo Tower , the defenders certainly believed it to be sufficient - " The complex was so well stocked with supplies and ammunition that the military garrison believed that , no matter what happened to the rest of Berlin , the zoo tower could hold out for a year if need be " . Armaments . The roof of the facility had four twin mounts of 12 . 8 cm FlaK 40 . As bombers took to higher altitudes , these were the only guns that could hit them . Each barrel could fire 10 to 12 rounds a minute , thus each twin mounted battery was rated to fire a maximum of 24 rounds a minute , and four twin mounts could fire as many as 96 rounds a minute . The guns were loaded electrically , with the ammunition fed into hoppers . Younger Nazi Youth , while officially not supposed to be combatants , assisted the military during the loading process . There was a range of smaller ( 20mm and 37mm ) anti aircraft guns on the lower platforms . Usage during the war . The primary purpose of the Flak Towers was to protect Berlin . Together with the Luftwaffe and a well organised fire brigade , the Berlin flak towers prevented the levels of the aerial attack damage that the RAF and the USAAF expected to occur , and had occurred in other German cities . The RAF Bomber Command had been endeavouring to facilitate firestorm s in Berlin , but had been unable to do so . The hospital facility , within the G tower , was used to treat wounded soldiers , shipped back from the frontline . Famed Luftwaffe ace Hans - Ulrich Rudel had his leg amputated there in February 1945 . As the bombing continued , the facility was also used to store art treasures to keep them safe . The Zoo tower in particular stored the Kaiser Willhelm coin collection , Nefertiti ' s head , the disassembled Altar of Zeus from Pergamon , and other major treasures of the Berlin museums . There had been the option to use the Tower as a command facility for the defence of Berlin , by General Hellmuth Reymann , the Reich Commissioner in charge of the cities defence effort . Reyman had refused to move his headquarters there . Goebbels ' headquarters was inside the tower , though he himself stayed in the Fuhrerbunker in his final days . Battle for Berlin . With Soviet and Polish troops entering Berlin in 1945 , civilians moved into the Zoo tower to escape harm . Soviet troops ( 150th and 171st Rifle Divisions ) attacked across the Moltke Bridge covering the River Spree . This was defended by German infantry and rockets , who were under pressure from Soviet tanks crossing the bridge , until the heavier anti aircraft guns from the Zoo tower could gain line of sight through the smoke . They destroyed the tanks and left the bridge covered in destroyed vehicles , which blocked further vehicles from crossing the bridge . The heavier 12 . 8 cm FlaK 40 anti aircraft guns obliterated Soviet armour , particularly when hitting it from the side . With thousands of civilians crammed into the facility , conditions in the Zoo tower towards the end were close to unbearable ; it was crowded and had little water , and the air was hard to breathe . As the Soviet armies advanced inexorably towards the centre of Berlin , around 10 , 000 German troops retreated to the Government district . The tower was never successfully assaulted , therefore it was still able to provide anti - tank support to the defenders in the Government district . For example , during daylight hours on April 30 , the Soviets were unable to advance across the open areas in front of the Reichstag to attack the building because of heavy anti - tank fire from the 12 . 8 cm guns two kilometres away on the Zoo tower . Soviet troops , not wishing to attack the facility , arranged the surrender of the troops inside . A Colonel Haller , negotiating on behalf of the tower , promised to capitulate at midnight . This was a ruse to allow for the forces in the Tiergarten area to make a break out through the Soviet lines and away from Berlin . This they did , shortly before midnight . The civilians then left the facility . Resistance to damage . The two towers resisted all attempts to destroy them by air attack and ground forces . The Soviets used their largest artillery pieces , their 203 mm howitzer , which they withstood . The towers resisted all attempts at destroying them during the war . In fact , even after the war with full access and planned demolitions , only the Zoo tower was completely destroyed . After the war and demolition . After the war the building was evacuated and Soviet troops systematically emptied it of its treasures and sent them to Moscow . It was 1947 / 48 , before the British Army blew up the tower complex . The smaller ‘ L ’ tower was blown up successfully on the first attempt on July 28 , 1947 . The larger ‘ G ’ tower required far more effort and explosives than the British engineers had expected . Initially , the G - tower was packed with 25 tons of explosives , and press had gathered to watch the demolition . The explosives were set off at 16 : 00 hours on August 30 , however when the dust cleared , the G tower still stood . One US journalist is reported to have remarked " Made in Germany " . With the third effort , the British spent four months preparing the building for demolition . Over four hundred holes were bored into the concrete structure , and packed with dynamite . A total of 35 tons of dynamite was used in the third try , which was successful . It was the only tower that was successfully completely blown up , though attempts were made on the others . After the demolition , the Berlin Zoo took over the land where the main G tower had been , and the smaller tower area is presently the site of the Hippopotamus park .