Yellowstone National Park
Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least , the highest being the Lower Falls of the Yellowstone River at .
Taum Sauk Mountain State Park
Mina Sauk Falls, the highest waterfall in Missouri, is reached via a rugged trail that makes a three-mile (5 km) loop from the highpoint parking area. The falls have cascading waters only during times of wet weather; at other times they are reduced to a trickle or less.