NIRGAL VALLIS

Perspective view of Nirgal Vallis, based on observations made by the Mars Global Surveyor. The feature observed on the planet Mars, at latitude -25, longitude 40, comprising a sinuous valley about 400 km (250 miles) long and about 5 km (3 miles) wide. The contours suggest meandering features that on Earth are caused in some flat river valleys by the erosion of the banks by the action of water. Somewhat similar features are found also on the Moon.