Photos from Grand Canyon National Park, Arizona, USA, by Tom Dempsey: South Rim, Yavapai Point, Maricopa Point, Powell Point, Hopi Point, Mojave Point, Pima Point, Grandview Point, Colorado River seen from Moran Point and Lipan Point, Bright Angel Trail, rider on horse train. A flying hummingbird feeds on Indian Paintbrush flower. Grand Canyon began forming at least 5 to 17 million years ago and now exposes a geologic wonder, a column of well-defined rock layers dating back nearly two billion years at the base. While the Colorado Plateau was uplifted by tectonic forces, the Colorado River and tributaries carved Grand Canyon over a mile deep (6000 feet / 1800 meters), 277 miles (446 km) long and up to 18 miles (29 km) wide. In 1979, UNESCO honored Grand Canyon National Park as a World Heritage Site.