Kochbrunnen by night
Wiesbaden has a lot of hot springs and 15 of them are bundled here at the Kochbrunnen. There's a fountain inside this pavillon spending the hot water rich with sulfur and other minerals. The temperature is around 65°C.
You can either drink the water (it's supposed to be good for your digestion) here or you can take a bath at one of Wiesbaden's bath houses (good for skin and organism).