The Makgadikgadi Pans in the Kalahari Basin cover a huge area (about the size of Portugal) and form the largest salt pan in the world. The most visited are Sua, Ntwetwe, and Nxai Pans. Makgadikgadi Pans National Park is on the western edge of this region, Nxai Pans National Park is just above it. A number of archaeological features and unusual landmarks such as rock formations and baobab trees can be found in this region. When there is sufficient rain and the Okavango floods are high, the Boteti River swells and flows through Makgadikgadi Pans National Park.