The best spa in the Cologne area is Mediterana (posting link below). It's new, modern, and has both nude and non-nude areas. First rate place, you'd think you're in the Med at a 5-star resort. Just 20 minutes east of downtown CGN.

[http://www.mediterana.de/]

Google maps--
http://maps.google.com/maps?q=Saaler...Q&z=16&iwloc=A