The last and most destructive bombing of Sofia during World War II took place on April 17, 80 years ago. In 1944, on April 17 at noon, 350 American bombers, accompanied by Thunderbolt and Mustang fighters, dropped 2,500 bombs on Sofia. 749 buildings were destroyed and many more were damaged. 128 people died and 21 were injured. In Bulgarian history, the date remains known as "Black Easter" and as the darkest day for the Bulgarian aviation, which lost 6 pilots who were protecting the skies over Sofia.

From November 1943 to April 1944, Bulgaria lost 27 aircraft out of 80 of its machines and 22 airmen. More than 2,500 fighters and heavy bombers were sent against Bulgaria. The Bulgarian defense shot down more than 100 planes. Enemy losses included 159 crewmen killed and 329 captured.