- British Commander-in-Chief in the Middle East, General Sir Archibald Murray, launches an assault on the Turkish coastal stronghold at Gaza in Palestine. The Turks are reinforced and prepared for the assault; they repulse their attackers inflicting over 6,000 casualties in the three-day long Second Battle of Gaza.
- The Battle of the Hills (or the Third Battle of Champagne) begins on the Western Front as a diversionary tactic during the Second Battle of the Aisne. Fighting continues until 20 April.
- British troops repulse German attacks near Hurtebise Farm and at Courcy
- Vladimir Lenin delivers his April Theses, in which he calls for Soviet control of state power
- The British hospital ships SS Donegal and HMHS Lanfranc are torpedoed without warning while carrying British wounded across the English Channel. The vessels sink; the Donegal with the loss of 29 wounded British soldiers and 12 of her crew, the Lanfranc with 22 dead.
SS Donegal pre WWI. Image in public domain.
