21 June 1917
- French troops on the Western Front recover nearly all ground lost near Vauxaillon and advance near Mont Cornillet
- Allied forces repulse a German attack on the Teton in Champagne
- Sailors of the Black Sea Fleet stationed at Sevastopol Naval Base mutiny. They claim that naval officers are planning a counter-revolution and demand that they be disarmed.
This entry was posted on June 21st, 2017.