North Sea: 3 old British cruisers Aboukir, Cressy and Hogue torpedoed and sunk within an hour by U9 (Weddigen). 1459 dead, 837 rescued by trawlers and Harwich Force.
Indian Ocean: Emden (125 shells) bombards Burmah Oil Company facilities, Madras. 50,000 t oil set on fire.
Pacific: Spee bombards Papeete (Tahiti); old French gunboat Zelee torpedoed.
FIRST BATTLE OF PICARDY (until September 26) begins as French Second Army reach Roye and Montdidier only to be blocked next day. French novelist Lieutenant Alain-Fournier killed, aged 27, leading platoon charge at Vaux-les-Palaneix. French brigade reoccupies Douai.
Belgium: 7 detachments (total 700 men) of Belgian volunteer cyclists ride out from Antwerp and cut German rail communications in three provinces.
Poland: New German Ninth Army (250,000) arriving north of Cracow; only 2 corps left in East Prussia. Grand Duke Nicholas holds war council at Kholm, regroup on Vistula to entrap Ludendorff and then invade Germany.
Galicia: Russians approach Przemysl (first shelled on September 18).
East Africa: Botha C-in-C East Africa. Coast Fort Majoreni repels 300 Germans, but British evacuate to Gazi, 25 miles (ca. 40 km) south of Mombasa (arriving September 26). German aim is to capture and wreck port from September 29 on, but cruiser Königsberg fails to appear.
Germany: FIRST BRITISH AIR RAID ON GERMANY. 4 RNAS Sopwith Tabloids from Antwerp attack Zeppelin sheds at Cologne and Düsseldorf. Flight Lieutenant Collet drops 3 x 20lb bombs (UXB) at Düsseldorf.
Western Front: RFC BE2 attempting to bomb kite-balloon intercepted by Albatros 2-seater; pilot wounded.
Britain: RNAS airship Beta patrols over fog-shrouded London to test visibility of potential Zeppelin targets.
Britain: Extra 50 MG’s per week ordered from Vickers for French Army.