The Battle of the Somme was the main Allied campaign on the Western Front during 1916. It took place between July 1 and November 18, 1916, along a 30-kilometre long front in the vicinity of the Somme River. The attack was preceded by a week-long bombardment of the German lines, with the idea that it would destroy the German defences and easily allow Allied troops to just walk across No-Man's Land and capture the German trenches. This didn't happen; to the surprise of the British, the German defences were mainly intact on the first day of the battle, July 1, 1916, and the bombardment had alerted the Germans that an attack was forthcoming. July 1 was, for the most part, a disaster for the British, especially in the vicinity of Beaumont-Hamel. The British Army sustained 60,000 casualties on the first day of the attack, the most ever sustained by Great Britain in a single day, with about 20,000 deaths. Entire battalions were wiped out, and as several of these were "pals battalions," comprising men from the same places, these casualties had an enormous social impact in many English towns. South of the Albert–Bapaume road, the British and French had greater success that day, making a small advance. Despite the casualties, British General Douglas Haig persisted in the attack. At the Battle of Flers-Courcelette, the tank made its first appearance in battle on September 11. The early tanks were rather unreliable but did have a devastating effect on German morale. By November 18, when the offensive was called off, the British and French had made gains of around 6 miles, not as far as the original objectives specified, but a greater gain than they had made at any time in the previous two years. However, the 600,000 casualties sustained have led many to comment that the gain in ground was not worth the casualties sustained.