The Salton Sea was created by accident during a botched irrigation project, and it took 2 years (from 1905 to 1907) to stop the flow. It's now a strange brew of natural salts and agricultural runoff, ringed with abandoned hotels, marinas and resorts and beaches composed entirely out of dead fish and barnacles. It's also a major stopover for migrating shorebirds, grebes and pelicans.

http://en.wikipedia.org/wiki/Salton_Sea

Salvation Mountain, a few miles east of Niland California, is the creation of Leonard Knight who has been living and working on this piece of desert since 1983. It was a real highlight of this trip for me - for the sheer colourful immensity of it all, obviously, but also because Leonard is a friendly guy who seemed really happy to show us around and talk about his work. You have to admire his energy and focus and dedication, no matter what you think of the message! From Niland, head east on Main St. for about 3 miles, just before Slab City.

http://www.roadsideamerica.com/attract/CANILsalvation.html
http://www.salvationmountain.us/menu.html