The land is predominantly flat to gently undulating tableland, although there is some hilly country, where mining is carried out. The Kalahari Desert is in the central and the southwest. The Okavango Delta, one of the world's largest inland deltas, is in the northwest and the Makgadikgadi Pans, a large salt pan lies in the north-central area. The Makgadikgadi has been established as an early habitation area for primitive man; This large seasonal wetland is composed of several large component pans, the largest being Nwetwe Pan, Sua Pan and Nxai Pan. Botswana's lowest elevation point is at the junction of the Limpopo and Shashe Rivers, at a height of . The highest point is Monalanong Hill, at .