While in orbit over southern Nevada, an astronaut onboard the International Space Station took this photo of brightly colored rocks and deep canyons in the Mojave Desert.
The Muddy and Virgin Rivers cut through the desert to deliver water to Lake Mead reservoir. The Muddy River flows through Moapa Valley, where it is bordered by agricultural fields and towns. The nearby Virgin River, by contrast, is bordered by dark vegetated areas and lacks urban structures. Both rivers empty into the Overton Arm, the northern part of Lake Mead that eventually merges with the Colorado River to the south.
Red-orange rock exposures near the center of the photo mark the Valley of Fire State Park (//parks.nv.gov/parks/valley-of-fire), located approximately 40 miles (60 kilometers) to the northeast of Las Vegas. At sunset, valley outcrops made of bright, rust-colored Aztec sandstone appear to be on fire, which led early European explorers to give the area its colorful name (//parks.nv.gov/learn/park-histories/valley-of-fire-history). This sandstone here formed from ancient sand dune fields that covered the area during the Jurassic Period. The slab was subsequently faulted and uplifted by tectonic forces, and then eroded by water and wind into the current landscape.
Significant archaeological artifacts have been found throughout Moapa Valley, with some dating back to 300 BCE. Among the finds are ancient petroglyphs (not visible in this photo) etched into the sandstone. Anasazi Native Americans occupied the area during that time, hunting, gathering, and building pueblo villages. The discovery of pit houses, pueblo walls, and other ancient cultural artifacts in what was to become Lake Mead caused people to dub the area "the Lost City". At the top of this photograph, the southern part of the Moapa River Indian Reservation is visible.