Yellowstone National Park was established by an Act of Congress on March 1, 1872, making it the world's first national park. Since then, the park has attracted more than 110 million visitors and become one of the best-loved national parks in the world. Yellowstone is known for its hot springs and geysers, the colorful Grand Canyon of the Yellowstone River and its wide array of wildlife. Navigate your way through Old Faithful and learn more about this geological wonder by checking out the sites below.