Hitler's decision to launch the offensive
Adolf Hitler orders the planning of a major surprise offensive in the Ardennes to break the Allied advance.
Secret troop concentration in the Eifel
German troops and armored divisions are secretly assembled in the forests of the Eifel, close to the Belgian border.
Start of the Battle of the Ardennes
In the early morning, German troops open the offensive with a massive artillery bombardment, followed by an attack across a broad front in the Ardennes.
The Malmedy massacre
German SS troops execute dozens of unarmed American prisoners of war near the hamlet of Baugnez near Malmedy.
Siege of Bastogne begins
German troops surround the strategically important town of Bastogne, where American troops of the 101st Airborne Division have dug in.
McAuliffe's famous reply 'Nuts!'
When the Germans send the encircled American defenders of Bastogne an ultimatum to surrender, General McAuliffe simply replies with 'Nuts!'.
Change in weather and Allied air support
After days of dense cloud cover, the weather clears, finally allowing Allied bombers and fighter planes to intervene.
Relief of Bastogne by Patton's Third Army
General George Patton's Third US Army breaks through the German encirclement and relieves the besieged troops in Bastogne.
Allied counteroffensive
American and British troops launch a coordinated counteroffensive to recapture the territories seized by the Germans.
End of the Battle of the Ardennes
The Allies fully restore the original front line, officially marking the German offensive as a failure.
Change in weather and Allied air support
The clearing skies enable the Allies to carry out supply drops over besieged Bastogne and to attack German armored columns from the air. This turning point in the weather contributes strongly to slowing the German advance and restoring Allied morale after days of confusion and retreat.