In a nutshell
The Rhine Falls is the most powerful waterfall in Europe, not because it is tall but because of how much water goes over it. At peak flow in summer several hundred cubic metres pass every second, and you feel it as much as you see it. Platforms built into the rock let you stand directly above the water, and small boats cross to the rock in the middle of the falls. On the north bank sits Schloss Laufen, the classic viewpoint, and the whole site is a short ride from Schaffhausen. Schaffhausen itself is worth the detour for its old town of painted facades and the Munot, a round fortress above the vineyards.
Landmarks

Rhine Falls
Europe's most powerful waterfall, seen from platforms on both banks.

Schloss Laufen
A castle perched directly above the falls, now home to viewing platforms.

Schlössli Wörth
A small castle right at the water on the opposite bank, with the jetty for the boats to the rock.
Activities

Boat ride to the rock
A short ferry ride right up to the rock in the middle of the falls.

Waterfall viewing platforms
Several platforms and paths, each with a different angle on the falls.
Tours to this destination
Photos of the Rhine Falls