 In the building of the Czechoslovak embassy, Yugoslavia signed capitulation in June 1941, after the Axis attack in World War II.In 1943, as part of the strategic bombing campaign within the scopes of the oil campaign against Nazi Germany, the U.S. began massive bombardment of the oil fields and refineries in Romania, known as the Operation Tidal Wave campaign.On their return, as Belgrade was important strategic point, the bombers threw their unused bombs on the city.