Though filled with an astonishing array of geologic wonders : geysers, hot springs, fumaroles, canyons, waterfalls, Yellowstone is perhap s the most remarkable as a wilder life sanctuary. Protected here are bison, elk, bears, moose, mountain lions, eagles, trumpeter swans, and a host of other animals. The world’s first national park, Yellow stone covers more than two million acres ( 810,000 hectares ) and draws thousands of visitors a year.