Located within the Yellowstone National Park in Wyoming, Grand Canyon of the Yellowstone is a 39 kilometre long, 1.2 kilometre wide, and 370-metre deep canyon. The geology of the canyon is not completely understood except that the canyon was formed as a result of erosion of the Yellowstone River. The canyon is between 10000 and 14000 years old. Visitors are invited to take one of the 3 hiking trails to the canyon which range from an easy 1.1 kilometre round trip to the 16-kilometre round trip. Majestic waterfalls can be found further down from the canyon.