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 .
Ribbon Fall
Ribbon Fall, located in Yosemite National Park in California, flows off a cliff on the west side of El Capitan and is the longest single-drop waterfall in North America. The fall is fed by melting winter snow; while therefore dry for much of the year, the fall is a spectacular 1,612 feet (491 m) in the spring. In exceptional years, an ice cone develops at its base during the winter months similar to that which usually forms beneath Upper Yosemite Fall. This deposit can reach a depth of 200 feet, versus 322 feet for the greatest depth of the ice cone beneath the Upper Fall and Lower Fall. It is the tallest, continuous waterfall in the United States.