The Ngorongoro Crater, which is the world's largest unbroken volcanic caldera. The crater is 610m deep and the floor is 260km squared. The steep sides of the crater mean that it has become a natural enclosure for a very wide variety of wildlife, including most of the species found in East Africa.
Aside from herds of zebra, gazelle and wildebeest, the crater is home to the "big five" of rhinoceros, lion, leopard, elephant and buffalo. The crater plays host to almost every individual specicies of wildlife in East Africa, and there are an estimated 25,000 animals within the crater. Lake Magadi in the centre of the crater is, like many in the rift valley, a soda lake supporting flocks of flamingo.