The place
Ngorongoro Crater, in short.
Ngorongoro is not a national park. It is a Conservation Area, which means Maasai families graze cattle here alongside the wildlife — the only place in Tanzania where that is permitted at scale. You will pass herders on the crater rim and sometimes on the floor itself.
The crater is the piece everybody comes for: an unbroken caldera with grassland, a soda lake, a fever-tree forest and a spring, all inside one wall. Nothing much needs to leave, so nothing much does. That is why the density is what it is, and why this is the most reliable place in Tanzania to see black rhino.
The Conservation Area is far bigger than the crater, and the rest of it is quieter and stranger: Empakaai and Olmoti craters, the Ndutu plains where the wildebeest calve, Olduvai Gorge, and the active volcano Ol Doinyo Lengai on the eastern edge.