Riverside Geyser, Yellowstone National Park, 1908

Yellowstone National Park, established 1872, was America's first national park. Approximately two square miles in area, Upper Geyser Basin contains the largest concentrations of geysers in the park. Located along the Firehole River, Riverside's eruption sprays as high as 75 feet, and it shoots water at an angle over the river, sometimes creating a rainbow effect.