magma chamber which could no longer support the weight above it. The mountain then developed a circular fracture which was left as a perfect rim around a flat-bottomed cauldron often more than a hundred square miles in extent. This is the structure that houses over 30,000 animals on the crater floor.
Ngorongoro Crater, extinct volcanic caldera in the Eastern (Great) Rift Valley, northern Tanzania. … Ngorongoro is thought to have formed about 2.5 million years ago from a large active volcano whose cone collapsed inward after a major eruption, leaving the present vast, unbroken caldera as its chief remnant.