The Grand Canyon (the known system of canyons formed by the Colorado River in the North of the Arizona state) is a very important touristic attraction of the United States, but, however, the latter gets short if we compare it to Valles Marineris, the biggest canyon system on Mars, and even in the hole solar system. Similarly to the Grand Canyon, this place could become a very important touristic attraction on the red planet when, in the future, there will be a human colony of big dimensions on Mars.
This enormous Martian structure covers almost a fifth part of Mars’ circumference, and it is found just under the Martian equator. It starts at the west, in Noctis Labyrinthus, a labyrinthine system of valleys and canyons, and it stretches towards the east until arriving at the Chryse Planitia basin.
Valles Marineris has a length of about 4,000 kilometres, an average width of 300 kilometres, and some of its zones reach a depth of 10 kilometres. If Valles Marineris was found on Earth, it would cover the United States, from Los Angeles to the Atlantic coast.
In comparison, the Grand Canyon has a length of only 446 kilometres, a maximum of 30 kilometres wide, and a depth of 1,6 kilometres.
Many theories about the formation of Valles Marineris have existed, and they have been changing over the years. Nowadays, many scientists believe that the formation of the Tharsis region could have helped the formation of the canyon. The Tharsis region contains some volcanos of enormous dimensions, for example, Olympus Mons, with a height of 25 kilometres.
According to this theory, the great volcanic activity that took place on the planet billions of years ago opened big fractures and cracks on the surface. These fractures, becoming larger over time, gave birth to what in our days we know as Valles Marineris.
The cracks that spread made the land sink, and this gave place to the apparition of diverse leaks from where underground water escaped (it is important to notice that at that time there was liquid water flowing through the planet’s surface). The liquid broke the edges of the fractures, enlarging them and taking the soil away as it flowed. As time passed, the canyon eroded, to form what nowadays is the biggest canyon in the solar system.