Mesa Verde National Park, Colorado
stone dwellings in cave-like alcoves created by erosion. But those same erosive forces may lead to the ruins’ destruction in Mesa Verde and other archaeological sites across the Southwest. Irregular weather patterns due to climate change have increased the frequency of the freeze-thaw cycles that cause cliffs to shed pieces of rock: Meltwater trickles into the cracks, expands as it freezes, and wedges off the outlying stone. The threat even prompted Mesa Verde officials to close access to Spruce Tree House in 2015.
Cliff Palace could follow. This past summer, the park dispatched climbers up the ruin’s surrounding walls and ceiling, where they tapped the rock with hammers to determine its stability. One rock-scaling mission ended up dislodging an 800-pound slab that splintered climbers’ scaffolding as it hurtled to the floor. Better make the .3-mile journey to North America’s largest cliff dwelling sooner rather than later. TRAILHEAD Cliff Palace Overlook (37.1678, -108.4731) SEASON April to October PERMIT Required ($5); obtain at the visitor center. CONTACT nps.gov/meve
Visit Cliff Palace on a guided tour. The dwelling contains 23 kivas and more than 150 rooms.