Big Bend

Declared in 1944, it is named for the great bend the Rio Grande traces on the border between Texas and Mexico, an international boundary that runs quite literally through the park. Since 2011 it has formed, together with two Mexican protected areas in Coahuila and Chihuahua, the El Carmen-Big Bend transboundary Biosphere Reserve, an unusual binational conservation effort between the United States and Mexico. The park combines Chihuahuan Desert, the isolated Chisos range and the river's own canyon, and is one of the best places in the country for stargazing, with barely any light pollution.