The German war plan called for the swif possible capture of Paris, hoping to knock France out of the war before Russia could fully mobilize its large but low-tech military. The fastest route to the French capital happens to run through Belgium, so the first battle of the war was a German attack on the Belgian city of Liège. Belgium was not part of any pre-war alliances and attempted to stay neutral in the war. The attack on Belgium brought the British Empire into the war, with British politicians citing their country's obligation to uphold Belgian neutrality. This was a risky move on Germany's part, but German war-planning long regarded a quick, decisive blow against France as the best possible hope of winning a two-front war. Right from the outset things did not go Germany's way. Liège (and other Belgian towns and fortifications near the Meuse River) fell, but the Belgians' determination to resist in the face of impossible odds did delay Germany's operations against France substantially, giving France and Britain critical extra days to prepare the defense of Paris.