<P> The battle began in dense fog at 4: 20 am on 8 August 1918 . Under Rawlinson's Fourth Army, the British III Corps attacked north of the Somme, the Australian Corps to the south of the river in the centre of Fourth Army's front, and the Canadian Corps to the south of the Australians . The French 1st Army under General Debeney opened its preliminary bombardment at the same time, and began its advance 45 minutes later . The operation was supported by more than 500 tanks, which helped to cut through the numerous barbed wire defences employed by the Germans . </P> <P> The first day of the attack, August 8, saw the attacking forces break through the German lines in dramatic fashion, with the Canadians pushing as far as 13 kilometres (8.1 mi) from their starting points . In many places the fog provided good cover for their advances in and through the furrows of the valley of the Luce river which ran through the centre of the Canadian's portion of the battlefield . The tanks were successful in this battle, as they attacked German rear positions, creating panic and confusion . The swift advance led to a rapidly spreading collapse in German morale that ultimately led Erich Ludendorff to dub it "the Black Day of the German Army" when he was told of the psychological impact on his men . </P> <P> Continuing to press the advantage gained on Day One, the advance continued for three more days but without the spectacular results of August 8, since the rapid advance outran the supporting artillery that could not be repositioned as quickly as the infantry advanced . By the 10th of August, the Germans had been forced to pull out of the salient that they had managed to occupy during Operation Michael in March, back towards the Hindenburg Line . Left without an enemy to fight or a plan to pursue the retreat the Allied advances in the Amiens sector including those of the Canadians petered out by 13 August and the Amiens operation was halted . </P> <P> The Canadians remained on the scene at Amiens until 22 August, consolidating their gains and prepared to defend against counter-attack . On the 23rd they were summoned to pull out and go into the line east of Arras for an attack that was to commence three days later . There they were stationed in the villages of Fouquescourt, Maucourt, Chilly and Hallu from which they would attack eastward toward the Hindenburg Line . </P>

What is the name of canada's most famous battlefield