Over Bulgaria… US B-17 and B-24 bombers attack Sofia.

Over Occupied Yugoslavia… US B-17 and B-24 bombers attack Belgrade.

In the English Channel and North Sea… The British Royal Navy and Bomber Command begin intensive mining of the approaches to the English Channel and as far north as the Danish coast. This operation is intended to prevent German interference with the D-Day invasion fleet. (It continues until June 5th by which time 7000 mines are laid. An estimated 100 light warships and other vessels are sunk by the mines.)