Day tripSalton Sea, Bombay Beach, Salvation Mountain, Slab City.
Salton Sea, California
Strange, stark shoreline south of the valley

The Salton Sea is California's largest lake, created by accident in 1905 when the Colorado River breached an irrigation canal, and it is now the strangest day trip in Southern California: a shrinking saline sea 235 feet below sea level, ringed by abandoned resort towns, a folk-art mountain, and one of the most important bird habitats on the Pacific Flyway.
What you actually see
The shoreline is bleached, the beaches are made of pulverized fish bone and barnacle, and the mid-century resort infrastructure at Salton City and Bombay Beach sits half-buried. It photographs unlike anywhere else in the state. Bombay Beach has been partially reclaimed by artists, with large-scale installations scattered across the sand and an annual spring art event.
Salvation Mountain and Slab City
At Niland, on the eastern shore, Leonard Knight's Salvation Mountain is a fifty-foot adobe-and-paint hillside covered in scripture and color, built by hand over three decades. Beyond it lies Slab City, an off-grid settlement on a former Marine base. Both are free and both are best visited in the morning.
Birds
The sea supports over 400 recorded bird species. The Sonny Bono Salton Sea National Wildlife Refuge on the southern end is the best access point, with viewing platforms and trails; winter is peak season for migrating waterfowl and cranes.
Practicalities
There is very little food, fuel or shade around the sea, and the smell can be strong when the water turns over. Bring water, fill the tank in Mecca or Brawley, and plan roughly ninety minutes of driving each way from Palm Springs.