This Mars Express image shows Reull Vallis, an outflow channel located at about latitude 42° South and longitude 102° East. The image was taken with a ground resolution of about 21 metres per pixel during Mars Express orbit 451 on 29 May 2004.
This is a view looking south-east across Promethei Terra, back up Reull Vallis and the junction with its tributary, Teviot Vallis. The channel seen here is approximately 20 kilometres wide and has cut into the surrounding plain to a depth of 1800 metres.