Okavango Delta 

Permanent marshlands and seasonally flooded plains make up the Okavango Delta in northwestern Botswana. It is one of the few significant interior delta systems that does not flow into a sea or ocean, and it has a nearly intact wetland system. One of the site's unique features is that the annual flooding from the River Okavango happens during the dry season, causing local plants and animals to synchronize their biological cycles with the seasonal rains and floods. 

It's a fantastic example of how climatic, hydrological and biological processes interact. Cheetahs, white and black rhinos, African wild dogs and lions, all live in the Okavango Delta which is home to some of the world's most endangered large mammal species. 

With its waters draining into the Kalahari Basin's arid sands, the Okavango Delta is the continent's largest endorheic delta and Africa's third largest alluvial fan. It's also in a near-pristine state as a mainly undisturbed wetland system. The biota, particularly the flooded grassland biota, has evolved unique growth and reproductive strategies to coincide with the advent of floodwater in Botswana's dry winter season. 

The Okavango River was "captured" by the geology of the area, which is part of the African Rift Valley System, resulting in the formation of the Delta and its numerous rivers, marshes, flooded grasslands and floodplains. With a length of 1,500 kilometers, the Okavango River is the third largest in southern Africa. 

The hydrology of the Delta is influenced by its dynamic geomorphological history, which determines water flow direction, flooding and drying of broad areas within the Delta system. The site is an excellent illustration of how the Okavango Delta's flora and animals have adapted their lifecycles to the annual cycle of rains and flooding, as well as the interplay of climatic, geomorphological, hydrological and biological processes that drive and shape the system. 

For its biodiversity and ecological uniqueness, the Okavango Delta was designated as a UNESCO World Heritage Site in 2014. (Source UNESCO)