- Royal Naval vessels HMS Otranto and HMS Kashmir collide off the Isle of Islay, Scotland. The Otranto sinks with the loss of 431 lives.
- A pro-Entente National Council of Slovenes, Croats and Serbs takes power in Zagreb, Yugoslavia, signalling the beginning of the breakup of the 600-year-old Hapsburg Empire
- British forces occupy Sidon in Syria