Western Front
Twelve Zeppelins of the German Navy were dispatched to attack London and the Midlands. Nine of the 12 Zeppelins reach East England (night September 23-24), drop 371 bombs causing 170 civilian casualties (151 in London). Of these, two 'super Zeppelins', the L32 and the L33, were shot down by the defences. L33 was seriously damaged by anti-aircraft fire over London and subsequently received further damage from a Royal Aircraft Factory BE2c of No.39 Squadron. The airship eventually grounded near Little Wigborough in Essex. L32 was shot down by a Royal Aircraft Factory BE2c, flown by Second Lieutenant Frederick Sowrey of No.39 Squadron, near Billericay in Essex. For many subsequent nights Londoners take refuge in underground railway from 1730 hours.
Kiffin Rockwell, an American aviator volunteer in France and the 1st American to shoot down an enemy craft, is killed in action. Rockwell was one of the founding members of the Lafayette Escadrille.
https://en.wikipedia.org/wiki/Lafayette_Escadrille
Battle of the Somme: After another victory Guynemer’s Spad VII hit by French 75mm anti-aircraft fire, but only suffers bruised knee on landing. Richthofen scores second victory, a Martinsyde of 27 Squadron (3 lost to Jasta 2 for 1 Albatros collision). Heavy aerial combat occurs over the Somme, with 54 kills in total claimed by both sides.
Germans begin work on the Siegfried (aka “HINDENBURG") Line.
https://en.wikipedia.org/wiki/Hindenburg_Line
Rawlinson postpones today’s operations to September 25. British 23rd Division advances east of Martinpuich.
French 305 mm railway gun near Bronfay Farm, Bray-sur-Somme:
http://imgur.com/E8PdwHy* © IWM (Q 78978)
Southern Front
Italian XVIII Corps captures Mt Cardinal in Cadore area but Austro-Hungarian mine explosion regains Mt Cimone d’Arsiero (Astico valley, Trentino) lost on July 23.
A battalion of Greek soldiers in Thessalonica defy orders and head to the front, as the country becomes further divided over neutrality.
Asiatic and Egyptian Theaters
Mesopotamia: RFC bomb Shumran bend German airfield near Kut, destroy 1 aircraft on ground (another hit on November 2).
Political, etc.
Germany: Germany blacklists 6 Dutch firms for trading with the Allied powers.