Coprates Chasma in the Valles Marineris on Mars, photographed by the Mars Express spacecraft. Appearing in the top half of this image, it ranges from 60-100 km wide and drops 8-9 km below the surrounding plains. G. Neukum/ESA/DLR/FU Berlin hide caption toggle caption G. Neukum/ESA/DLR/FU Berlin 13.7: Cosmos And Culture The Siren Call Of The Wilderness Can Be Heard On Mars, Too March 26, 2013 The wilderness is not just a thing, it's a need. It's an idea that has grown up with humans and it will follow us from this planet to the next, and beyond. Commentator Adam Frank plots our future course.