valles marineris largest rift mars
It extends over more than a sixth of the circumference of the planet's equator east of the Tharsis region, which could contribute to the extreme stress of the lithosphere during its formation. Rift itself is divided into many smaller canyons, some of which may be incurred as additional water erosion.
The average width is about 200 km, but can sometimes reach up to 500 km. The slopes are cut into the depth of 7 km. The length is 3800 km.