Covers nearly 810 hectares of bush, grassland and forest, from the plains of the Serengeti National Park to the East Arm of the Great Rift Valley . It includes the spectacular Ngorongoro Crater, the largest caldera (a large, more or less circular volcanic depression) in the world. Ngorongoro is part, with Olmiti and Empakaai, of the most famous craters for their geology. It is home to endangered animal species, such as the black rhinoceros, and wildlife that lives there throughout the year.