There's no greater feeling for a surfer than a nice long ride. In the ocean, that might mean 20 to 30 seconds. But on an odd freak-of-nature wave that rolls up the Dordogne River in Bordeaux, France, every month, it can mean 20 to 30 minutes. It's called the Mascaret, and it's one of several tidal bores around the world (created when extreme fluctuations in lunar tides push a swell from the ocean upriver). I'd been hearing about a hard-to-get-to bore in the Amazon and rumors of a huge one in China. But it was the Mascaret that intrigued me most – riding through French wine country in the festival-like atmosphere that brings surfers, SUPers, and kayakers to the Dordogne every month.

"The first time I saw the bore, I couldn't believe it," says Patrick Audoy, who many consider to be the French Laird Hamilton, and who has been surfing the Mascaret and other bores around the world for 16 years. "It was a surprise because the river is so far from the sea." The Mascaret is a mellow waist-high roller that can be ridden for miles, even by beginners. Unlike the typically cliquish ocean-surfing culture, the French bore riders welcome newbies. Audoy even loaned me a longboard (the nearest surf shops are two hours away on the coast) and gave me tips on riding it.

A couple of hours before the Mascaret arrived, we tailgated with about 30 other surfers in the St. Pardon harbor parking lot and sucked down a few pre-bore pints at the Café du Port. At 30 minutes before, everyone grabbed their boards and paddled downriver. There, we sat waiting on the riverbank, hurling the occasional mud ball at one another to break the tension. The Mascaret started as a hiss, growing to a low roar as the wall of water rounded the bend, careening upstream at 15 mph. There are usually around five tightly spaced waves, but it's the first and second waves you want to ride, as they're the only ones capable of propelling you a long distance. Paddling furiously, I caught the first swell. The initial 30 seconds were pure chaos as riders jockeyed for position, shoulder-to-shoulder – at least half the riders missed the wave, while others soon fell off.

I began walking forward on the board once I got comfortable, even making gentle turns across the face. Minutes went by and my quads were screaming, but the pain faded as I surfed past rolling vineyards, ancient farmhouses, and the medieval Castle of Vayres. Twenty full minutes and three miles later, the wave finally faded before I did. I climbed out onto the grassy riverbank. We faced a very long walk back to the pub, but all I could think about was coming back tomorrow and doing it all over again.

More Information: Fly to Paris; connect to Bordeaux. The bore is at its biggest and best in summer. Lacanau on the coast has some of the best ocean surfing in France, is much less crowded than Biarritz, and has board rentals.