[rudolfm]

Regarding Berlin, the Vabali now asks people not to walk around naked, so forget that one.

The Kristalltherme has clothing optional times, all Wednesday and part Sunday. Still 50% are naked. In the saunas everone must be naked. I find it a bit fun walking around naked in front of clothed women, so if you enjoy that you might like those times. You can travel there with an express train and a bus in one hour for 4€. Station name is "Kristallbad". As they have a bar in the water with good drinks, it might be better not to go by car.