Lowlands fringe the coast, which is marked by several islands, the largest being Zanzibar, Pemba, and Mafia. Inland, the land rises to a vast plateau. Here the terrain is 2,000 to 4,000 feet (610 to 1,220 m) above sea level and is generally rolling to flat.
Two arms of Africa's Great Rift Valley cut through Tanzania. One branch, a deep chasm, follows the western border; the other extends northeastward from Lake Nyasa to Kenya. There are also several highland areas where the land rises abruptly from the surrounding plateau. These areas are mainly along the margins of the Great Rift Valley. In the northeast, near the Kenya border, is a volcanic region. Here snowcapped Kilimanjaro, an inactive volcano, rises to 19,340 feet (5,895 m), the highest elevation in Africa. The Pare and Usambara mountains are nearby; the Kipengere Range is in the southwest.
Africa's three great lakes—Victoria, Tanganyika, and Nyasa—are partly in Tanzania. Except for Lake Victoria, all of Tanzania's lakes lie in the Great Rift Valley. Lakes Tanganyika and Nyasa, in the west, are large, deep bodies of freshwater; those in the eastern rift, such as Lakes Natron and Eyasi, are small and saline and have no outward drainage.
Tanzania has few large rivers except during the rainy season. Those draining into the Indian Ocean include the Pangani, Wami, Rufiji, and Ruvuma. The Malagarasi, the Kagera, and other streams in the west are part of the Nile, Congo, or Zambezi river systems. Little use is made of the rivers for navigation, hydroelectric power, or irrigation.
High temperatures and a distinct rainy season (from November to May) and dry season (the rest of the year) mark the climate throughout most of Tanzania. The coast is the hottest and most humid part of the country. Dar es Salaam, for example, has average monthly temperatures between 75° and 82° F. (24° and 28° C.) and receives about 40 inches (1,020 mm) of rain each year. Because of its increased elevation, the plateau has slightly lower and more variable temperatures than does the coast. Rainfall totals roughly 10 to 35 inches (250 to 890 mm) a year, except near Lake Victoria, where considerably more rain occurs. The highlands, because of their greater height, are relatively temperate regions.
Forests grow mainly in the highlands and along the coast. Elsewhere there are steppe and savanna grasslands; some areas are semideserts.
Within Tanzania are many of the animals commonly associated with Africa, such as the lion, leopard, rhinoceros, giraffe, and zebra. To protect them against possible extinction, brought on by the steady encroachment of humans, the government maintains numerous game reserves. Among them are Serengeti National Park, Ngorongoro Crater, and Selous Game Reserve. Safaris are permitted, but only for sightseeing and photography.