Paul Souders/ Worldfoto / Red algae and salt formations, Lake Natron, Ol Doinyo Lengai, Tanzania

Gerry Ellis / Soda and algae formations near shore of Lake Natron, Great Rift Valley, Tanzania

Mitsuaki Iwago / Blue Wildebeest (Connochaetes taurinus) herd with Burchell's Zebra (Equus burchellii) crossing river during migration, Serengeti

Paul Souders/ Worldfoto / Streams and Lake Natron, Ol Doinyo Lengai, Tanzania

Paul Souders/ Worldfoto / Red algae and salt formations, Lake Natron, Tanzania

Gerry Ellis / Greater Flamingo (Phoenicopterus ruber) flock flying over Lake Natron, Great Rift Valley, Tanzania

Richard Du Toit / Soda and algae crust on Lake Natron, Tanzania

Ingo Arndt / Aerial view of tropical forest, Gombe Stream National Park, Kakombe Valley, Tanzania

Mitsuaki Iwago / Blue Wildebeest (Connochaetes taurinus) herd migrating, Serengeti

Mitsuaki Iwago / Cape Buffalo (Syncerus caffer) herd migrating, Serengeti National Park, Tanzania

Mitsuaki Iwago / Blue Wildebeest (Connochaetes taurinus) aerial view of herd migrating, Serengeti

Paul Souders/ Worldfoto / Red algae and salt formations in alkaline Lake Natron, Tanzania