Following the Normandy Invasion the greater part of the German Air Force (Luftwaffe) was transferred to the West.

[citation needed] The air defences of Vienna were aided by a ring of anti-aircraft batteries set up around the city and three pairs of Flak towers.

Due to the increasing lack of fuel, by autumn 1944, artillery on the ground was the only defence against air raids.

Some Vienna factories were moved to bomb-proof sites such as caves (e.g. the Seegrotte near Hinterbrühl) or hidden in other ways.

[citation needed] In February and March 1945, 80,000 tons of bombs were dropped by US and British aircraft, destroying more than 12,000 buildings, and 270,000 people were left homeless.