What battle delayed the allied advance west in WW2?

The Battle of the Bulge, fought from December 16, 1944, to January 25, 1945, delayed the Allied advance west in World War II. This surprise German offensive aimed to capture the port of Antwerp and split the Allied forces. Despite initial successes, the Allies ultimately regrouped and countered the attack, but the battle significantly slowed their progress and diverted resources during the harsh winter months.