At Cambrai in November 1917, a tank force of over three hundred tanks punched a hole four miles deep into the German lines in the space of a single morning, an advance comparable in size to that made at Passchendale in four months. But the Germans counter-attacked and the result of the battle was a virtual draw, with the front lines shifting slightly. However, the battle of Cambrai marked a major turning point in the course of the war - and military history as a whole.The era of trench warfare was coming to an end and technology was beginning to reign supreme on the battlefields of Europe.