Births on May 21

Tinus Osendarp, Dutch sprinter and police officer (d. 2002)

Martinus "Tinus" Bernardus Osendarp (21 May 1916 – 20 June 2002) was a Dutch sprint runner.

9 Jan

Gallipoli Campaign
World War I: The Battle of Gallipoli concludes with an Ottoman Empire victory when the last Allied forces are evacuated from the peninsula.
21 Feb

Battle of Verdun
World War I: In France, the Battle of Verdun begins.
25 Feb

Battle of Verdun
World War I: The Germans capture Fort Douaumont during the Battle of Verdun.
9 Apr

Battle of Verdun
World War I: The Battle of Verdun: German forces launch their third offensive of the battle.
31 May

Battle of Jutland
World War I: Battle of Jutland: The British Grand Fleet under the command of John Jellicoe, 1st Earl Jellicoe and David Beatty, 1st Earl Beatty engage the Imperial German Navy under the command of Reinhard Scheer and Franz von Hipper in the largest naval battle of the war, which proves indecisive.