Geology
Caves
6 destinations along 6 roads
Caves are what water writes underground. Rain turns faintly acidic, seeps into limestone, and over ages dissolves the rock from within — the same slow chemistry behind the decorated chambers of Timpanogos, the ice pocket at Mossy Cave, and Lehman Caves under Great Basin's peaks. Homestead Crater went warm instead, a geothermal spring domed in its own mineral crust; Grand Canyon Caverns went bone-dry, the largest dry cavern in the country. That one is also a Hualapai burial place, not a curiosity — the ground beneath the road keeps its own meaning.