Swimming in the Spree River would be a dubious activity were it not for the Badeschiff, a sublimely sci-fi, urban oasis comprised of a floating swimming pool and two Finish saunas that look like space ships. Ladies get the sauna to themselves on Wednesdays and Saturdays from 10am-2pm, while men settle for alone time on Monday nights from 10pm-3am. A health food bar, massage treatments, relaxing footbaths and the occasional open-air concert round out the offerings.