I doubt that Seebad Enge has changed much since the 1920's. It is a floating wooden swimbath. You pay a moderate fee to enter (6 or 7 CHF?) and can stay for as long as you like. There are changing rooms, showers, toilets, a cafe with books and newspapers. There is a men's side, a women's side, and a mixed area in the center. All ages can comfortably sunbathe, or go down a short ladder to swim in the lake. They have three floats in the lake as well, which also appear to be men's on one side, women's on the other, and mixed on the middle float. You can see under the bathhouse through the gaps in the planking as you are changing--I liked seeing fish pass under me.) It rocks very gently with the lake waves, and is really quite idyllic and calming, especially with jet lag or after too much running around. Topless (as in most of europe) is acceptable. I don't think I saw anyone going fully naturist, but I can't speak regarding the men's side. There are plenty of ways to swim without paying, at various spots around the lake, but if you are willing to pay a little, this is a very relaxing and healthy way to spend an hour or two (or more).
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