The Battle of the Bulge was a major event late in WW2. At the time of the battle the Allies were in control of most of Western Europe, and advancing toward Germany. Hitler organized a major offensive to push through the Ardennes region and retake the port of Antwerp Belgium. If Germany could retake Antwerp they could greatly hamper the Allies ability to supply their Armies and maybe stop their advance.

The Allies were caught totally by surprise when Germany started its offensive on 16 December 1944. After being over-run and pushed back, the Allies dug in at the town of Bastogne Belgium. Bastogne sits on key roads that the Germans needed to move their forces to Antwerp. The Allies had air superiority but bad weather favored the Germans and kept the Allies from using it. The Germans set siege to Bastogne but were unable to defeat the American troops holding the town. By 25 January 1945 the Battle of the Bulge was over and the German offensive had been destroyed. This battle was the single biggest and deadliest in Europe that the American Army engaged in during WW2.

More Info: en.wikipedia.org