Ngorongoro Crater

Millions of years ago, between two and three by geologists' estimates, a volcano roughly as tall as Kilimanjaro blew itself apart and caved in on itself. What remains is the largest unbroken, dry volcanic caldera on Earth. The floor lies about 610 m beneath the rim and covers 260 km², ringed by walls that climb as much as 600 m. That natural amphitheatre keeps a huge amount of wildlife inside one self-contained ecosystem. The surrounding Ngorongoro Conservation Area spreads over 8,292 km² and is a UNESCO World Heritage Site with an unusual brief in Tanzania: wildlife protection and traditional Maasai herding share the same land.

At any one moment some 25,000 large mammals are thought to live on the crater floor, which gives it one of the planet's highest wildlife densities. Seeing all of the Big Five during a single drive is a realistic prospect, something very few African parks can honestly promise. The crater holds one of East Africa's last viable groups of critically endangered black rhino, along with tightly packed lion prides and big herds of wildebeest and zebra that stay all year instead of migrating. Lake Magadi, a soda lake on the floor, draws flamingos by the thousand when conditions suit them.

A typical visit is one concentrated day. You descend a steep track to the floor, spend several hours driving across open grassland, acacia woodland and the swampy Lerai forest, and climb back up in the afternoon. Close to the rim sits Olduvai Gorge, the "Cradle of Mankind", where Louis and Mary Leakey unearthed key hominid fossils, among them Homo habilis. It makes a rewarding stop on the way through. Maasai families still graze cattle inside the conservation area under long-standing arrangements, so conversations with them here tend to feel natural rather than staged.

Because the animals do not leave, Ngorongoro works in every month. The skies are clearest and the viewing easiest in the dry spells of June to October and January to March. The crater lies a comfortable 180 km from Arusha and nearly always forms the second half of the classic northern circuit alongside the Serengeti. One night on the rim is usually all that is needed to see it properly before moving on.