English: Waw an Namus, an extinct volcano in Libya, appears as a smear of dark basaltic ash and tephra that contrasts sharply with the light-colored sand of the Sahara Desert. South of the ash field, mud streams have begun the slow process of eroding the tephra and ash away. The ash field extends around a much smaller caldera that is about 4 kilometers (2 miles) wide. Within the caldera are three small salty lakes ringed with vegetation. The edge of a cinder cone is also visible near the center of the caldera.