what exactly is that canyon mentioned above?
It is a steep-sided canyon carved by the Colorado River in Arizona, United States.
Introduction
 is a steep-sided canyon carved by the Colorado River in Arizona, United States. 
are the oldest rocks in the world in the grand canyon Yes, the rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old. is there any river flowing through or alongside it? Yes, Colorado River
It is a steep-sided canyon carved by the Colorado River in Arizona, United States. It is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States., it is long, up to wide and attains a depth of over a mile
Grand Canyon Grand Canyon Grand Canyon
Introduction Introduction Introduction
The Grand Canyon (, , , ) is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile (). The Grand Canyon (, , , ) is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile (). The Grand Canyon (, , , ) is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile ().

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Grand Canyon [SEP] Introduction
The Grand Canyon (, , , ) is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile (). The canyon and adjacent rim are contained within Grand Canyon National Park, the Kaibab National Forest, Grand Canyon–Parashant National Monument, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area and visited it on numerous occasions to hunt and enjoy the scenery. Nearly two billion years of Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted.