African Elephant, Ngorongoro Crater

Photograph by Chris Johns

Once a giant volcano that collapsed inward millions of years ago, the Ngorongoro Crater is today the largest unflooded and intact caldera in the world. Lone bull elephants with imposing tusks—survivors of the ivory trade in decades past—roam the crater floor, while matriarchal elephant herds prefer the surrounding highland forests, which fall away to the tawny plains of the Great Rift Valley.