Sky and grassland rule Africa's enormous savannas.

Nearly half of Africa, over 13 million square kilometres, is savanna (5 million square miles).

From south of the Sahara and Sahel to north of the continent's southern tip, these grasslands cover central Africa.

The Serengeti Plains, one of Africa's many savannas, is the most famous.

From Kenya's Maasai-Mara to Tanzania's Serengeti, the plain covers 30,000 square kilometres (11,583 square miles).

The Serengeti has a high concentration of huge mammals.

Over one million wildebeest (Connochaetes taurinus) circle the Serengeti Plains following seasonal rains.

Their grazing and trampling help fresh grasses grow, while their faeces fertilises the soil.