The 1941 German Bombing of Belgrade caused untold damage to the library, reducing the building to rubble and destroying invaluable cultural heritage. As the result of Nazi firebomb raids, the roof of the building that used to house the library at the time was destroyed by the flames, along with its last floor. The Children's Library was in operation throughout the war and library services became available to other users as well in early 1943. After World War II, the library started regular operation on January 18, 1945. Library holdings were increased from 20,000 units at the end of the war to 39,813 in 1948.