20. The American Army and units of the German Army fought side-by-side near the end of WW2
Castle Itter, in the Austrian Tyrol, served as a prison camp during the Second World War, where French VIP prisoners were held by the German SS. Near the end of the war in Europe a combined force of American troops, German troops led by a Waffen SS officer, and former French prisoners combined to defend the castle against an attack by about 200 German soldiers of the SS 17th Panzer Grenadiers. The Germans who fought alongside the Americans and French were members of the Wehrmacht, led by an officer who had changed over to support the Austrian Resistance movement in the closing days of the war. The battle took place on May 5, 1945, when Hitler was already dead, just two days before the Germans surrendered.
The allies sustained just one fatality during the battle to defend the castle against the attacking SS troops. He was Major Josef Stangl, the SS officer who had defected with his troops, eleven men, to the American side. The Germans, 16 Americans, and a few of the French prisoners held off the attack until a relief column from the American 104th Infantry Division arrived. Among the prisoners present during the battle was French General Maurice Gamelin, the former prime minister Edouard Daladier, and Charles de Gaulle’s sister, Marie Cailliau. It was the only time in either of the World Wars when German troops fought alongside Americans.