Once upon a time every surfer on Earth knew that consistent big waves – ones topping 30 feet on the face – broke only at Hawaii's Waimea Bay and Mexico's Todos Santos. So in 1991, when Surfer magazine published a small picture of a wetsuited man riding a giant wall of water somewhere near San Francisco, every local had to ask himself, "Wait a minute, what the hell break is that?"

Every local but Jeff Clark, of course, the surfer in that photograph. Clark had been surfing Mavericks alone since 1975. In 1990, he finally talked a couple of guys into riding with him – days later, another small crew followed. But it took another two years before Surfer magazine published a full-scale exposé on the break, giving away the location – 20 miles south of the Golden Gate Bridge and less than a mile offshore – and the mind-blowing revelation that, on a coastline crawling with surfers, within sight of the highway, a world-class monster lived in virtual anonymity.

Mavericks is the product of a geological anomaly, a vast cleft in the underwater continental shelf that lets open-ocean swells reach the coast without losing any size or power.

"It was clearly one of the most dangerous and technical big waves in the world," says Matt Warshaw, author of 'Mavericks: The Story of Big-Wave Surfing.' "It looked just barely on the edge of the possible." That perception got confirmed in December 1994, when a photographer caught local teenager Jay Moriarity falling down a wave so horrifying it made the 'New York Times.' Only days later, half-a-dozen big-wave superstars took a redeye over from Hawaii. Local legend Mark Renneker recalls being amazed by the Hawaiians' recklessness.

"It's such a warped wave that you can do everything right and still get nailed," Renneker says. "It has this strange quality of dropping out beneath you while pushing up against you."

Mark Foo, the most famous of those Hawaiians, learned the hard way: He fell on a takeoff and drowned.

Tow-in surfing stole the limelight for a while, when Laird Hamilton pioneered the use of Jet Skis for towing surfers into 70-foot beasts at a break called Jaws off Maui. But the hardest part of big waves had always been the paddling, jumping to your feet while that wave face went vertical. So it wasn't long before the tow-in novelty wore off and guys refocused on the paddle game.

That's how history repeated itself in March 2011, when Mavericks drew another crew of Hawaiian pros – including Sion Milosky, a 35-year-old who had just become famous for riding the largest paddle-in wave of all time, an Oahu 60-footer.

Milosky got worse than hurt. Like Foo, he fell on a takeoff and drowned, but not before having the kind of session that will keep guys coming back for as long as there are storms in the Pacific and surfers hungry to ride them.

"The best big-wave surfers in the world were out there, and Sion was ruling," said surfer Ken Collins at the time. "He must've caught six 50-foot waves." Among the half-dozen places on Earth where that's even possible, Mavericks remains the most punishing.