Black Forest Wave runs in the Metzelgraben canal through Pforzheim, a channel that eventually feeds the Nagold, and it's an entirely grassroots build—volunteers under the blackforestwave club spent years testing a prototype with the Karlsruhe Institute of Technology before getting the water-law permit to install the real thing. The structure can be lowered into the canal or raised out depending on flow, and surfers adjust its angle with hydraulic cylinders controlled through an app, keeping the roughly 15-foot-wide face rideable across a range of water levels. It's a club-run operation, so expect to book a slot and pay a small fee rather than just paddling up. It's intermediate-friendly and playful, and one of the more unusual builds in Europe given it runs through a city canal rather than a natural river.