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

Paul Bertner / Slime mold,Amani Nature Reserve, Tanzania

Richard Du Toit / Patterns in alkaline salt crust on surface of Lake Natron, Tanzania

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

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

Martin van Lokven / Blue Wildebeest (Connochaetes taurinus) walking, Serengeti National Park, Tanzania

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