The Battle of the Bulge was the last German offensive in the west during the Second World War. It commenced in December 1944 following the Normandy invasion of June 1944 when Allied forces swept rapidly through France but became stalled along the German border in September. On December the 16th, taking advantage of weather that kept the Allied aircraft on the ground, the Germans launched a counter-offensive through the hilly and wooded Ardennes country and advanced 50 km into Belgium and Luxembourg. Their aim was to divide the Americans and the British and retake the vital seaport of Antwerp. They created a 'bulge' in the Allied lines, but their advance was halted near the Meuse in late December. Managing to avoid being cut off by an Allied pincer movement, the Germans withdrew to their own lines in January, but heavy losses, including some 220,000 casualties, contributed to their final collapse in the following spring.
The battle is notorious for the atrocious war crimes committed by both sides, notably the slaughter of prisoners of war taken during the offensive. Research Battle of the Bulge