Mojave Desert Once part of an ancient inland sea, the Mojave desert was formed by volcanic action and by materials deposited by the Colorado River. Now, it is a vista of mountains, boulders, washes, joshua trees, and cacti. Clean air, sunny days, star filled nights, outstanding views, abundant wildlife, rockclimbing, hiking, biking, and relaxation make it a favorite day trip for the city-weary residents of Los Angeles. Edwards Air Force Base once attracted visitors to see the space shuttles landing, but the base was shut down years ago during the federal government defense cutbacks. Most of the visitors, though, are simply passing through on their way to and from the City of Sin, Las Vegas.