The Stuibenfall is a big waterfall between the villages of Umhausen and Niederthai. There are plenty of hiking trails in the area, and one of them follows the falls pretty closely on the southern side.
If that's not enough excitement, on the north side is a exhilarating Via Ferrata, grade C. It starts easy, including some hiking sections, but higher up are some vertical parts. And near the end you, the route crosses the waterfall, where you walk on a steel wire - expect to get wet! There is plenty of iron though, and it's never very difficult.