9th April - 16th May
British Empire forces fight the Battle of Arras to support a French offensive.
In early 1917 the man in charge of the French Army on the Western front, General Nivelle, had a plan for a huge offensive that he said would break through the German line and knock them out of the war.
General Haig of the British Army agreed (after being persuaded by the new Prime Minister, lloyd George) that the British would launch an attack to support the French. Their attack would be near Arras in France.
The British attack went quite well - they captured some important positions including Vimy Ridge, which was taken by a brilliant attack by Canadian soldiers. But the French offensive was in trouble. They weren't making as much progress, and just a few days into the offensive a mutiny began - some of the soldiers refused to fight the enemy. With the French Army crumbling, General Haig had to end the British attack at Arras in May.
An Allied soldier in an observation post disguised as a tree trunk.