Learn about the Valles Marineris

Valles Mariners, the largest canyon system on Mars. On the far western side of the Valles is a graben, Noctis Labyrinthus; Candor and Ophir Chasmas, the products of erosion and structural forces, are in the centre. The entire structure is more than 4,000 km (2,500 miles) long and has an average depth of 8 km (4.8 miles). This picture is a composite of medium-resolution black-and-white and low-resolution colour images taken by the Viking 1 and Viking 2 spacecraft.