Grand Canyon National Park
If asked to choose an iconic U.S. natural site, many people would opt for the Grand Canyon. Grand Canyon National Park allows visitors to see this massive geographic feature up close, and between 4 and 5 million people come to experience the mile-deep gorge annually. Trails, scenic overlooks and canyon-side paths offer plenty of snapshot-worthy views, and the Colorado River, which runs through the canyon, is a popular rafting destination. The canyon's more-remote North Rim, which is little more difficult to access than the popular South Rim, offers ambitious tourists a chance to appreciate the canyon without having to fight their way through the camcorder-toting masses.