Chiricahua National Monument

The southwestern United States encompasses desert landscapes, sandstone formations and archaeological sites from several pre-Columbian cultures. The region spans Utah, Arizona, New Mexico and Colorado, featuring geological structures shaped over millions of years by wind and water erosion. National parks such as Canyonlands and Capitol Reef display canyons, mesas and rock spires in shades of red, orange and ochre. The area preserves evidence of the Ancestral Puebloans, who built cliff dwellings and communal structures between the 12th and 14th centuries. Sites like Bandelier National Monument and Gila Cliff Dwellings provide access to these habitations. Chaco Culture National Historical Park documents a pre-Hispanic trading center with multistory stone complexes. Petroglyphs at locations such as Three Rivers and the petrified trees of Petrified Forest National Park offer additional historical records. The Navajo Nation administers Monument Valley and the Navajo Zoo, while Hubbell Trading Post operates as a functioning 19th-century trading post. Volcanic features mark Sunset Crater and El Malpais, while White Sands covers more than 275 square miles (700 square kilometers) of gypsum dunes. Glen Canyon and the man-made Lake Cochiti provide water access in this largely arid region. Elevation differences range from the Organ Pipe Cactus Desert to Great Basin National Park with its ridges above 13,000 feet (3,900 meters).

The selection presents geological formations from basalt columns in Northern Ireland to salt flats in Bolivia. It includes glaciers, volcanoes, canyons, waterfalls, and coral reefs. These geological structures were shaped by natural forces such as erosion, tectonic movements, and volcanic activities over millions of years.

Arizona contains geological formations spanning millions of years alongside evidence of Spanish colonial settlement and prehistoric cultures. The landscape includes sandstone canyons such as Antelope Canyon X and Canyon de Chelly National Monument, extensive desert areas with saguaro and organ pipe cacti, and volcanic remnants at Sunset Crater. Historical sites include Spanish missions like Tumacácori, pueblo ruins at Montezuma Castle, and mining towns such as Bisbee and Jerome. The state holds significant paleontological sites at Petrified Forest National Park, where fossilized tree trunks from the Triassic period lie exposed, and cave systems like Kartchner Caverns with active speleothem formations. The Vermilion Cliffs region displays layered sandstone formations including The Wave, while the Chiricahua Mountains show volcanic rock pinnacles formed from welded ash. Waterfalls such as Havasu Falls and Grand Falls result from geological faulting and seasonal water flow. Archaeological sites document occupation by the Hohokam, Sinagua, and Ancestral Puebloans between 300 and 1400 CE. Tonto Natural Bridge forms one of the largest travertine bridges in North America, while Besh-Ba-Gowah shows Salado culture construction methods from the 13th century. The territory spans from the Sonoran Desert in the south to the Colorado Plateau in the north, creating distinct climate zones and ecosystems within a compact area.

Rock pillars and spires shaped by erosion stand as natural monuments across various locations worldwide. These geological structures, known as hoodoos, display different colors and shapes based on their mineral composition and environmental conditions. From the red rocks of Utah to the limestone formations of Turkey, these sites present geological formations created over millions of years through wind and water erosion. These formations develop through differential erosion, where softer rock layers erode faster than harder layers, leaving slender columns often capped with protective harder rock. Visitors find such structures in desert landscapes, canyons, and plateaus where conditions favor their formation and preservation. The color palette ranges from white to orange, red, and gray, depending on the minerals present such as iron oxide, limestone, or clay.