The Blythe Intaglios (or geoglyphs) are found near Blythe, CA in the Colorado Desert. They include figures of humanoids and tailed quadrupeds that were created anywhere from 450 to 10,000 years ago. Some believe the glyphs represent mythic characters from Quechan history and cosmology, while others see it as evidence that the region is La Cuna de Aztlán, the legendary homeland of the Aztec.
The present is just a continuation of the past; and the site has not remained fixed in time, as modern peoples have added to the messages of the ancients. The most visible additions are the swirling tire tracks that some ethnographers believe represent an Atomic Age creation story, depicting the tracks of subatomic particles first seen in bubble chambers and since sublimated into the collective unconscious of drunk rednecks in pickup trucks.
(Indirectly via BLDGBLOG.)