The crossword solution for the term 'When Doubled, A German City' is 'BADEN' (5 letters). BADEN is a city in Germany located in the state of BADEN-Württemberg. It is situated on the western bank of the Neckar river in the foothills of the Black Forest mountain range. The city is known for its hot springs and spa culture, which has been popular since the Roman era. When doubled, BADEN becomes 'BADEN Baden', which is a popular tourist destination in Germany.