The Largest Canyon in the Solar System
Posted in Astronomy at 20:30 on 29 May 2020
… that we know of, is Valles Marineris on Mars.
It shows up stretching across the centre of Mars in this mosaic image as seen on Astronomy Picture of the Day for 24/5/20.
Valles Marineris is over 3,000 kilometres long, 600km wide and in parts 8km deep. (Compare the Grand Canyon, only 800 kilometers long, 30km across, and 1.8km deep.)
The three round features on the left are the Martian Shield Volcanoes, one of which, Olympus Mons, is the highest mountain in the Solar System.