WW2 War Diary for Sunday, March 21, 1943:
Eastern Front
Southern Sector: Germans recapture Belgorod, northeast of Kharkov. Spring thaw slows down operations.
Sea War
Atlantic: US submarine Herring sinks U-boat U 163 in Bay of Biscay.
Home Fronts
Britain: After tunnelling for 5 months 21 IRA men escape from Londonderry Jail; 15 reach Eire and are interned.