Palo Duro Canyon

Drive across the flat Texas Panhandle south of Amarillo and the ground suddenly falls away into Palo Duro Canyon, a gorge about 120 miles (190 km) long, up to 20 miles (32 km) wide and about 800 feet (240 m) deep. Texas Parks and Wildlife calls it the second-largest canyon in the country. The Prairie Dog Town Fork of the Red River carved it into the Caprock Escarpment of the Llano Estacado, exposing bands of red Permian mudstone, Triassic sandstone and white gypsum. Hoodoos such as the Lighthouse, the canyon's signature formation, stand where harder caprock has protected softer layers beneath.

Comanche, Kiowa and Southern Cheyenne bands sheltered in the canyon for generations until September 1874, when Col. Ranald Mackenzie's cavalry attacked their camps during the Red River War, capturing and killing about 1,200 horses and forcing the people onto reservations in Indian Territory. Ranching followed. Palo Duro Canyon State Park, built partly by the Civilian Conservation Corps, opened in 1934 and covers about 28,000 acres, the second-largest park in the Texas system. Each summer its amphitheater hosts the outdoor musical TEXAS.

• Red River of the South
  Rust-colored border river between Texas and Oklahoma carved by
• Texas
  The Lone Star State, second-largest in area and population located in
• The Great Plains
  The vast grassland that rises to the Rockies part of
• The Grand Canyon
  A mile-deep gorge carved by the Colorado River related