Battle of Dunkirk
Encircled, the British, Belgians and French launched Operation Dynamo (May 26 – June 4) and later Operation Ariel (June 14–25), evacuating Allied forces from the northern pocket in Belgium and Pas-de-Calais, beginning on May 26. (see Battle of Dunkirk) The Allied position was complicated by King Leopold III of Belgium's surrender the following day, which was postponed until May 28.