In WWII what was the first German city to be taken by the Allies?

Aachen

Yes, on October 21st 1944, good answer Coldfuse.

Aachen (Aix la Chapelle in French), probable birthplace of Charlemagne (742 -814 CE), was the capital of the Holy Roman Empire (Formally 843-1806 CE), which, after the unification of Germany as a nation state in 1871, was called by some as the First Reich, with Nazi Germany referring to itself as the Third Reich. (The 1871-1918 Empire was counted as the Second Reich.) This allowed Hitler to claim a connection to Charlemagne, Kaiser Wilhelm I, and a supposedly better past. The area was a Stone Age flint quarry before becoming a Celtic city. Around the first Century, the Romans knew it as Aquis-granum, and used the mineral spas there for relaxation for the military. It is located at the border of Belgium, the Netherlands and Germany.