• Officially known as the Third Battle of Ypres, Passchendaele became infamous not only for the scale of casualties, but also for the mud.
• Ypres was the principal town within a salient (or bulge) in the British lines and the site of two previous battles: First Ypres (October-November 1914) and Second Ypres (April-May 1915). ]
• The flatness of the plain made stealth impossible: as with the Somme, the Germans knew an attack was imminent and the initial bombardment served as final warning. It lasted two weeks, with 4.5 million shells fired from 3,000 guns, but again failed to destroy the heavily fortified German positions.
• The infantry attack began on 31 July
• Constant shelling had churned the clay soil and smashed the drainage systems. The left wing of the attack achieved its objectives but the right wing failed completely.
• Within a few days, the heaviest rain for 30 years had turned the soil into a quagmire, producing thick mud that clogged up rifles and immobilised tanks.
• It eventually became so deep that men and horses drowned in it.
• On 16 August the attack was resumed, to little effect. Stalemate reigned for another month until an improvement in the weather prompted another attack on 20 September.
• The Battle of Menin Road Ridge, along with the Battle of Polygon Wood on 26 September and the Battle of Broodseinde on 4 October, established British possession of the ridge east of Ypres.
• Further attacks in October failed to make much progress. The