Mars.
Valles Marineris would hold the whole of Earth's Grand Canyon is one of its side canyons.
In addition, its largest volcano -- Olympus Mons -- is larger than any volcano on our planet.
Earth, has the Grand Canyon
depends on how close you are when looking at it Funny! Seriously, the name itself, Copper Canyon, is deceptive. It leads one to believe that it is a 'single' canyon, when it is not. Copper Canyon consists of six (6) different canyons. The Grand Canyon is a 'single' canyon, therefore the two cannot be compared. For those who vehemently believe that Copper Canyon is larger, that is like saying the the Great Lakes should be considered an ocean or a sea because they intersect. Geographical descriptions do not work that way. Copper Canyon is unique, but it is not bigger than the Grand Canyon.
Mars
Valles Marineris is on the Planet Mars.
Mars
Mars is home to the largest and deepest canyon, it is about 2500 miles long and 4 miles deep.
Fearless Planet - 2008 Grand Canyon 1-6 was released on: USA: 16 December 2007 Japan: 4 June 2009
Mars Valles Marineris is the largest canyon found in our Solar System. Located in the Southwestern Hemisphere of Mars, the canyon stretches 2,500 mi (4,000 km) across the Martian surface and covers approximately one fifth of the planet's circumference. This canyon is also 400 mi (650 km) wide at places and have depths of over 3.8 mi (6.1 km) deep.
Presently the largest canyon system discovered so far is on Mars and is called Valles Marineris, it extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep
It is one of the most breath-takingly beautiful spots on this planet.
Besides being one of the most sublimely and majestically beautiful places on our planet, there is nothing special about the Grand Canyon.____________The Grand Canyon is not the deepest or widest canyon in the world, but it does reveal nearly two billion years of the planet's geological history. The eroding action of the Colorado River over the slowly uprising plateau has caused ancient layers of rock to be exposed. This too may not be unique, but it is without a doubt special.
Mainly to view one of the most awesomely beautiful sights on this planet.
Other than view one of the spectacularly beautiful sites on our planet, not much.