WATCH: What caused the giant valley on Mercury?

Deeper than the Great Rift Valley and more than 1000 kilometres long, a huge valley on Mercury is thought to have an interesting reason for its existence.

The geographical feature on the surface of the smallest planet in the solar system is thought to be due to the planet shrinking, resulting in the buckling of its outer crust.

This results from a high resolution map created from stereo images taken by the NASA Messenger spacecraft.