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.