Carlsbad Caverns switchbacks in NM: a 20 degree grade
Tucked beneath the scenic Chihuahuan Desert, in Eddy County in the U.S. state of New Mexico, near the base of the Guadalupe Mountains, the switchbacks are the natural entrance to the Big Room, in Carlsbad Caverns. Pedestrians only.
Located on the southeastern part of New Mexico, in the rocky slopes and deep canyons of Guadalupe Mountain range, the trail leads by switchbacks into the mouth of the cave. These switchbacks are steep, and with each step the ambient light grows dimmer. It’s a very good walkway with about a 20 degree grade and is a mile and a quarter of switchbacks leading 750 feet below the surface.
Located within the Carlsbad Caverns National Park, the paved trail is a 1.25-mile (2.01km) descent, pretty narrow and very steep. This switchback trail into the Big Room is closed to vehicles and patrolled by park rangers often. Carlsbad Cavern is a labyrinth of more than 300 limestone caves, carved over 250 million years ago and includes a large cave chamber, the Big Room, a natural limestone chamber which is almost 4,000 feet (1,220 m) long, 625 feet (191 m) wide, and 255 feet (78 m) high at the highest point. It is the third-largest chamber in North America. The road to reach the caverns is the scenic Carlsbad Cavern Highway (New Mexico Highway 7).
Pic: By Daniel Mayer - Taken by uploader, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1404826