Geysers, hot springs and roaming bison
Established in 1872, Yellowstone sits on top of a vast volcanic system, and it shows. Old Faithful erupts on a predictable schedule, the Grand Prismatic Spring glows in bands of blue, green and orange, and boardwalks thread through steaming geyser basins. The Grand Canyon of the Yellowstone has two thundering waterfalls, and the Lamar and Hayden valleys are among the best places in North America to see bison, elk, bears and wolves. Stay on the boardwalks, keep well back from wildlife, and add a day for the jagged Teton Range just to the south.