Having visited hundreds of sites all over the world, including Lascaux and Chauvet in France and the Côa Valley in Portugal, [archaeologist David S. Whitley] believes the Coso Petroglyphs to be one of the most important rock art sites on earth.
Mr. Whitley estimated that there may be as many as 100,000 images carved into the dark volcanic canyons above the China Lake basin, some as old as 12,000 to 16,000 years, others as recent as the mid-20th century.
In Rock Art Redefines Ancient in today's New York Times.
The Coso Rock Art District, just off the road between L.A. and Vegas, has defied disturbance because it also operates as a firing range for U.S. Naval air weapons.
It's open for visitors (during which time I'm pretty sure they turn the bombs off). You can arrange a tour through the Maturango Museum »
You can also take a Flickr tour: