LAKE NATRON This is an active volcano in northern Tanzania lying just south of Lake Natron. It is located in the Rift Valley, in the heart of Masaai country, and locally regarded as a sacred mountain. Looking north from its summit crater the hot barren salt flats of Lake Natron stretch into the distance. To the south stretch the Crater Highlands and the Ngorongoro Game Reserve. The eastern horizon is dominated by Kilimanjaro and to the west the forested escarpments and hills comprising the western slopes of the Rift Valley. About every seven years Lengai erupts and plumes of smoke billow out of the crater. Almost always it is possible to walk across the crater floor, often to the edge of the molten lavas.