Ngorongoro Crater is indisputably one of the natural wonders of the world. Two million years ago, a volcano collapsed on this site and formed a perfect caldera, an unbroken natural bowl with a diameter of 12 kilometres. The crater is like a giant natural zoo, with a dense concentration of wildlife including lions, leopards, elephants, baboons and rhinos.Ngorongoro is also home to members of the Maasai tribe who continue to pursue a traditional way of life in and around the Crater, which has symbolic and historical significance in Maasai culture.