This decisive battle on 6 September 1914 stopped the Germans winning the war in one swift strike. Only 30 miles from Paris, the French commander Joffre gambled on a counterattack that split the German army in two and forced a retreat. Famously 600 Paris taxis were used to carry reservists to the battlefield.
The second battle of Ypres in April 1915 (the first was in August 1914) was the only major German attack of the year. To break through the trench lines, the Germans used poison gas for the first time, allowing them to advance several miles. However, the British recovered and the German attack was thwarted.
Falkenhayn, the German commander, decided to 'bleed France white' by attacking Verdun, a historic fortress town that the French felt honour-bound to defend. From 21 February 1916 the Germans made some progress, but the battle became a bloody stalemate. The French suffered 550,000 casualties and the Germans 434,000 from the battle which lasted until December.
The Somme campaign was moved forward to 1 July 1916 to help relieve the pressure on the French at Verdun. Although losses were high, it was not the complete disaster it has been painted, and the British attacks aided the French. In September the first ever tank attack took place between Flers and Courcelette, and the campaign lasted until November.
Also known as the Third Battle of Ypres, Passchendaele in July 1917 was an attempt by the British to remove the Germans from the high ground around Ypres. Unfortunately the weather was unusually wet and the battlefield became a morass of mud. However the attack kept the German army occupied while the French army recovered from a widespread mutiny by its soldiers after yet another failed offensive.
After holding the German spring offensive at the second battle of the Marne, the Allies showed in the battle of Amiens that they could win the war. On 8 August 1918, called the 'black day of the German Army' by its commander Hindenburg, the Allies broke through the German lines with many tanks. The attack hit German morale and the Allied success forced the Germans to ask for an armistice in November 1918.