On the Western Front there was stalemate.

During the year Great Britain began to use conscripts.

January: Final evacuation of British and dominion troops from Gallipoli.

February 21: Following an enormous bombardment on February 21, the German Fifth Army attacked the fortified but lightly garrisoned region of Verdun, lying in the middle of a salient jutting into the German zone. The first German assault, on a 13-km (8-mi) front east of Verdun, gained considerable territory and captured a key position, Fort Douaumont. The French as a symbol of their determination defended Verdun.

March 6: The next German attack against the western face of the salient, was eventually checked by French counterattacks. For the rest of the month attacks and counterattacks resulted in significant loss of life on both sides.

German casualties at Somme, 1916. 
Within hours 60,000 British soldiers were dead, wounded or captured for the gain of 7 miles

July 1: The British infantry, following an artillery barrage, were mowed down by German machine guns. By nightfall the British had lost about 60,000 men, 19,000 of them dead, the largest loss of life in a single day in the history of the British army. The French made greater advances, since the Germans had not expected them to participate in the initial assault and consequently were surprised by the attacks south of the Somme. One objective of the offensive had been accomplished. The Germans hesitated, the eastern front needed extra units and Verdun was considered less important than defending other areas.

August: Romania entered the war against Austria but was rapidly overrun.

September: British tanks had been secretly shipped to the front, used for the first time in battle, and spearheaded an attack. Despite the surprise their appearance caused to the Germans, the tanks were under-powered, unreliable, slow, and too few in number to gain a decisive victory (out of 47 brought up, only nine completed their tasks in the battle).

We travelled miles of trenches to reach the point we occupy. Some of the places we passed were liquid mud up to our knees. The town we passed through was an absolute ruin, not a house that is not blown to bits. I never saw the like of it, not a soul anywhere. I can't describe the look it has. It made me shiver - wooden crosses on the roadside and in places in the town marking the heroes' death - what devastation - a day of judgement more like. Man builds and then builds machines to destroy, well he seems to have made a better job of destroying this town.