Apart from the urgent need of relieving the pressure on Verdun, a British offensive was due as a contribution to the common task; and the front on which it would be made did not offer a great variety of choice. Whatever attractions other localities may have held out yielded to the Somme, where the French and British lines met by Maricourt, and an advance side by side was the nearest approach the Allies had yet made to unity of command or even of design. The combined effort was to be concentrated on a single front of twenty-five miles from Gommecourt, half-way between Albert and Arras, to Fay, five miles above Chaulnes. If it achieved the success that was hoped, it would roll up the German line north towards the Belgian coast and render untenable in the south and east the great salient of the German front. The retreat which the Germans effected to the Hindenburg lines in the spring of 1917 was the least that was expected from the summer offensive of the year before. But Germans are seldom idle, and for months they had been silently and unobserved preparing to counter the vast storm of explosives about to break on their trenches. That wire-entanglements however extensive, and trenches however intricate, could be obliterated had been proved, and the Germans were ready with their prophylactic on the ground that was chosen for attack. The rolling downs of the Bapaume ridge offered natural attractions to an army sick of the water-logged flats of Flanders, but they also afforded the Germans depth and scope for their vast underground chambers which no artillery could destroy; and these defences more than any other single cause defeated the British thrust at Gommecourt and Serre. The Battle Of The Somme