Like the Nazca Lines in Peru, a group of giant geoglyphs in the California desert can best be appreciated when viewed from the air. Known as the Blythe Intaglios, the ancient drawings of humanoid figures and animals may be thousands of years old. They were created using the intaglio process, in which a top layer of dark soil is scraped away to reveal lighter colored soil underneath. More at Weird U.S.
Photo (click to enlarge) by Ron Gilbert from Wikipedia Commons.