World War One Diary for Monday, August 20, 1917:
Ypres: Since July 31, 17 German divisions ‘used up’ according to General Kuhl, CoS to Rupprecht. British attack profitably with 7 tanks.
Verdun – Second Offensive Battle of Verdun (until September 9): Guillaumat’s French Second Army, with 18 divisions vs 12, takes German defences north of Verdun on 11-mile front to depth of 1 1/4 miles including Avocourt Wood, Mort Homme, Hill 240 and 5,000 PoWs (until August 23). German Fifth Army (forewarned) previously evacuated Talou ridge and other positions.
Russia: Kornilov orders Cossack concentration within rail distance of Petrograd or Moscow (or on August 19).
Baltic Provinces: Russians evacuate some positions southwest of Riga (until August 22) 3-8 miles to shorten line, plus stores and sick from city itself. German Eighth Army begins approach march for Riga operation (August 22).
Atlantic – Penultimate British Q-ship success: Acton sinks UC-72 (damaged Q-ship Penshurst on August 19).