Salton Sea

It was an engineering mistake. In 1905 the Colorado River, running high, broke through a poorly built diversion cut on the Alamo Canal and turned south into the Salton Sink instead of the Gulf. It kept pouring for the better part of two years before the Southern Pacific closed the breach in February 1907, by which time it had filled a basin more than two hundred feet below sea level and created what is still the largest lake in California. The basin had held water before, under the ancient Lake Cahuilla, whose old shoreline is legible on the hills to the northwest.

For a few decades the accident looked like a gift. Speedboats set world records on it in 1929, the state stocked it with corvina and sargo in the 1950s, and yacht clubs and beach subdivisions went up around the shore. But the lake has no outlet and is fed almost entirely by farm runoff, so it grows saltier every year. The fisheries collapsed, the resorts emptied, and the water is now well saltier than the Pacific.

Now the shoreline recedes and the exposed playa blows dust into a valley with some of the worst childhood asthma rates in California, while the geothermal brine underneath it holds one of the world's largest known lithium deposits. The stops worth making are Bombay Beach on the east shore and the state recreation area on the north.