Waw an Namus, Oasis of Mosquitoes, is a volcanic field, cone and caldera in southern Libya, deep in the Sahara Desert. The inside of the caldera houses an oasis of rich foliage and three small salt lakes of variable color which are the reason for the volcano’s name. A volcanic field of dark basaltic tephra flow extends 10–20 kilometres (6.2–12.4 mi) around the caldera. The dark field’s vast size allows it to be easily seen from space. Due to the fresh water at the volcano, Waw An-Namus was always an important watering point for the caravans.
By NASA’s Earth Observatory – The Operational Land Imager (OLI) on Landsat 8 (http://earthobservatory.nasa.gov/IOTD/view.php?id=86054), CC BY 2.0, Link