Aeons ago, Etosha Pan was the bed of a vast lake; today what remains is a glittering, silvery-green salt pan that stretches across roughly 5000 square kilometres. Etosha is protected by the Etosha Pan National Park surrounded by savannah plains and woodlands supporting large herds of elephants. When dry, the pan sustains little life except for the algae that gives it its distinctive colour, and migratory birds that use it as a pit stop, but with heavy rain it becomes a shallow lake where flamingos breed, pelicans wade and feed, and a variety of mammal species come to quench their thirst, including leopards, lions, white rhinos, hunting dogs and antelopes.