Trona Pinnacles
Trona, California
About 200 odd rock spires are grouped on a flat desert expanse, like a seasonal refuge for extraterrestrial snowbirds. It's the Trona Pinnacles, strange geologic formations convenient enough to LA to be the shooting location for over 30 commercials, TV shows and sci-fi film projects each year.
The pinnacles were formed from tufa that grew into the formations while underwater in a giant inland sea during the Pleistocene Ice Ages. There are three distinct groupings of pinnacles, with the northernmost cluster easiest to reach by car.
The alien nubbins of Trona have become all too familiar props as planetscapes: planet Shakari in cheesy Star Trek V, a crash site in Lost in Space, a more spectacular crash site in Tim Burton's Planet of the Apes. Apparently there's nothing preventing adding your own otherworldly adventure to the list.
Official signs advise not to try visiting during or after heavy rains, and that some of the clusters are only accessible with rugged 4-wheel drive vehicles. The tufa is fragile, and visitors should exercise caution.