"Stitched" panoramic shot of Ngorongoro Crater taken from the rim. Ngorongoro Crater is the world's largest unbroken volcanic caldera. The Crater, which formed as the giant volcano exploded and collapsed on itself around 2 million years ago, is 610m deep and the floor is 260km². 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. The Munge Stream drains Olmoti Crater to the north, and is the main water source draining into Lake Makat, the seasonal salt lake in the center of the Crater. The Lerai Stream (which is used for the tourist hotels and campgrounds) drains the humid forests to the south of the Crater, and it feeds the Lerai Forest on the Crater floor - when there is enough rain, the Lerai drains into Lake Makat as well. The other major water source in the Crater is the Ngoitokitok Spring, near the eastern Crater wall. There is a picnic site here open to tourists, and a huge swamp fed by the spring, and inhabited by hippopotamus, elephants, lions, and many others. Many other small springs can be found around the Crater floor, and these are important water supplies for the animals and local Masaai, especially during times of drought.
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 species of wildlife in East Africa, and there are an estimated 25,000 animals within