- Herbert Vincent McGrath is killed in action in France
- His Majesty’s Hospital Ship Britannic hits a German mine and sinks in the Aegean Sea four nautical miles off Kea, Greece. The converted Olympic-class ocean liner is the largest of its kind in the world and a sister ship of the Titanic. Thirty of the 1,066 people on board are killed.
- Arthur Zimmermann is appointed German Foreign Minister, following the resignation of Herr Gottlieb von Jagow
- German troops on the Eastern Front occupy the city of Craiova in Romania
- Emperor Francis Joseph of Austria dies after 66 years on the thrones of Austria and Hungary. He is succeeded by his great-nephew Archduke Charles, who wants to take Austria-Hungary out of the war.