A national monument and national park of the United States, the Grand Canyon is a geological wonder viewable from space and one of the Seven Wonders of the Natural World. For many tourists traveling across the U.S., including travel writer Kathy Petrino, this is a must-stop location. Just more than 275 miles in length in Arizona, the Grand Canyon reaches 18 miles wide yet more than a mile deep. Kathy Petrino notes that more than 6 million people visit this grand attraction annually in recent years to simply see its magnitude or for camping, hiking, horseback riding, kayaking and more. Adventures down the Colorado River deep within the Grand Canyon are plenty allowing for more than a quick visit for sunrise, sunset or picture-taking at the UNESCO World Heritage site.