Yellowstone National Park
The great idea of a national park at Yellowstone spawned a worldwide movement for conservation. There are now over 50 national parks in the United States alone. I recently got a chance to visit Yellowstone National Park before the summer crowds hit. It gave me a chance to visit the popular spots without the massive traffic backups that unfortunately plague the park. I came away most impressed by the Grand Canyon of the Yellowstone River. The sheer size and color of the canyons made it all that much more magnificent than in any picture I could ever take. If you get the chance go, if only for that.