May 31, 2017 all-day
May 31 June 1, 1916. The largest naval battle of WWI involving 250 ships, including battleships took place in the North Sea near Jutland, Denmark. The combatants were Britain’s Grand Fleet and Germany’s High Seas Fleet. The outcome was inconclusive, but the cost was great: 8,600 lives were lost and 25 ships sunk.
Image: Public Domain, Wikimedia Commons