By late 1944, Allied forces had pushed Nazi Germany back in much of Europe, retaking Paris and Rome.
US Army intelligence determined that the thick evergreen forest of the Ardennes in Belgium would be a good place to rest and reorganize combat units, as enemy forces in the area were largely low-quality troops.
The Nazis, however, were preparing a great counteroffensive, forming up 30 crack divisions that would cut the Allied army in two and push for the Belgian port of Antwerp.
On the morning of December 16, 1944, more than 200,000 German troops and almost 1,000 tanks drove into the Ardennes, across an 85-mile stretch of the front line, running from southern Belgium to the middle of Luxembourg.
Stories abound of German paratroopers dropping behind the lines, of English-speaking Nazi troops impersonating Americans, and of massacres of American prisoners of war at Malmedy.
Bad weather held Allied air power in check, and many American troops were caught off guard. The US 106th Infantry division was encircled in hours, and two out of three soldiers were caught or killed. US forces settled into wholesale retreat, save for a few pockets of soldiers who fought on but were quickly isolated, though they held crucial road junctions.
Allied troops from all over the Western Front rushed to the 50-mile bulge the German offensive pushed into the front lines.
Gen. George S. Patton’s Third Army arrived at the end of December, and weather improved, but it took until January 28, 1945, to return the front line to where it was on December 15.
Below, you can see photos from the first weeks of the frigid six-week battle that caused 67,000 American and 100,000 German casualities.
German soldiers, wearing heavy winter gear, walk past a burning American half-track in the Western Front in the Battle of the Bulge in World War II, December 1944. This photo is from a batch of film captured from the Germans by American forces.
German infantrymen pass burning captured American vehicles during the drive into Allied lines on the Western Front in the Battle of the Bulge in December 1944 during World War II. This photo is from a batch of film captured from the Germans by American forces.
An unidentified young American soldier, captured by German troops during their counterattack in the Belgian Ardennes region, leads a march of prisoners at an unknown location in December 1944.
This captured German photo shows two dead American soldiers, stripped of all their equipment, as they lie face down in the slush of a crossroad in an unknown village near Buellingen, in the Province Liege in Belgium, in December 1945.
American tanks and armored gun carriers drive over snow-covered terrain toward Samree, Belgium, December 1944, during World War II.
A seriously injured GI lays in the snow in Belgium, December 1944.
Troops from the American First Army cautiously search a wooded area in Belgium during the Battle of the Bulge, December 24, 1944, during World War II. They were looking for German parachute troops.
An infantryman from the 82nd Airborne Division goes out on a one-man sortie while covered by a comrade in the background, near Bra, Belgium, on December 24, 1944.
A King Tiger German tank ran against a building in an unnamed Belgium town on December 26, 1944, where it was knocked out of action.
Standing on a snow-covered battlefield, these American infantrymen of the 4th Armored Division fire at German troops, in an advance to relieve pressure on surrounded US airborne units, near Bastogne, Belgium, on December 27, 1944.
A two-man patrol, a bren-gunner and a piat-gunner, in Belgium on December 31, 1944. Snow had fallen on the two previous days.
German prisoners of war are seen as they carry the body of an American soldier through deep snow, during the Battle of the Bulge, in the Ardennes sector of Belgium, in late 1944.
A soldier runs past a burning German half-track in the recaptured town of La Glieze, Belgium, in 1944 during the Battle of the Bulge in World War II.