Ngorongoro Crater

Ngorongoro Crater is an actually existing, inactive volcanic caldera of the African continent, and it is part of the Ngorongoro Conservation Area  (NCA), a natural game reserve in Tanzania. It's the largest unbroken crater rim in the world, and it's considered one of the seven natural wonders of Africa. The crater, along with the Conservation Area itself, are part of the Serengeti-Mara ecosystem. Ngorongoro Crater is also the main setting for the webcomic Africa, and it's split into several zones, which include Lerai Forest, Lake Magadi and Gorigor Swamp.