During the Second World War, Bulgaria declared war on the US and UK on 13 December 1941 and in late 1943 and early 1944 the US and UK Air forces conducted bombings over Sofia. As a consequence of the bombings thousands of buildings were destroyed or damaged including the Capital Library and thousands of books. In 1944 Sofia and the rest of Bulgaria was occupied by the Soviet Red Army and within days of the Soviet invasion Bulgaria declared war on Nazi Germany.