There’s a wave near Bordeaux that travels up the river. Against the current. And people surf it.
It’s called the mascaret (a tidal bore): the rising Atlantic tide pushes into the Gironde estuary, crashes into the river’s own flow and builds a wall of water, often a train of waves, that runs upstream. You get it on the Dordogne (Saint-Pardon, in Vayres, is the classic viewing spot) and on the Garonne, between Langoiran and Podensac.
I had it filed as “happens twice a year”. Wrong. It forms with every big spring tide (coefficient above ~90), so around 50 surfable days a year. The equinoxes, in March and September, just bring the biggest ones, which is probably where my “twice” came from.
The wave usually tops a metre, up to 2.5 m on the best tides, and you can ride it for about ten minutes straight. Only around 60 places in the world get one.
Ten minutes on a single wave. Not bad.