Its average depth is about 1 mile (1.6 kilometers), though the canyon ranges from 2,400 feet (731 meters) deep below Yavapai Point on the South Rim to 7,800 feet (2,377 m) deep at the North Rim. The canyon wends 277 miles (446 km) along its sinuous path.
In 1994, the Guinness Book of World Records crowned the Yarlung Tsangpo Grand Canyon in the Himalayas as the world's longest and deepest canyon. Its depth reaches 17,567 feet (5,382 m) and its length 308 miles (496.3 km).
On average, the canyon is only 10 miles (16 km) wide from rim to rim, but crossing by foot takes 21 miles (33 km), and driving by car is a 251-mile (403 km), five-hour odyssey. At least the trip is through scenic backcountry.
Australia wins the prize for the world's widest canyon, with its Capertee Valley edging out the Grand Canyon at a little more than 18 miles (30 km) wide.
Geologists are drawn to the record of Earth's history contained in sedimentary rocks blanketing the Vishnu schist. These relatively unaltered sediments stopped accumulating about 230 million years ago, and are older than the dinosaurs. Though no dinosaur bones have ever been found in the park, geologically recent fossils, including 11,000-year-old sloth bones, have been found in canyon caves. Many marine fossils and animal tracks also appear in the National Park's rock layers.
One-armed war veteran John Wesley Powell, who charted the Colorado River's course in 1891 and 1892 in a wooden boat, was the first to consistently use the name "Grand Canyon."
Did the river carve the canyon all at once? Or was there an ancient gorge waiting for the young river, ready to capture its flow? One recent study found some rocks at the western end were eroded and exposed at the surface 70 million years ago. Active debate continues, with scores of research studies ongoing in the canyon.