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Okavango River, BotswanaThis piece is part of Water Grabbers: A Global Rush on Freshwater, a special National Geographic News series on how grabbing land—and water—from poor people, desperate governments, and future generations threatens global food security, environmental sustainability, and local cultures. A bushman paddles a canoe along the Okavango River, southern Africa's fourth longest waterway. The Okavango starts in Angola and 1,000 miles (1,600 kilometers) later drains into Botswana's Moremi Wildlife Reserve, where it creates an unusual landlocked, delta-like oasis in the Kalahari Desert.This oasis, protected by the reserve, is a near-pristine maze of papyrus reeds, channels, and islands that serve as a watering hole for a host of species, including zebras, wildebeests, lions, cheetahs, cranes, and wild dogs.Flooded annually by seasonal rains, the swampy Okavango Delta can expand to a size of 6,500 square miles (16,800 square kilometers)—an area larger than the state of Connecticut.The river itself winds through dense forest, dry savanna, and dunes as it makes its way south. While it provides much-needed water to an arid landscape, the river remains mostly untouched by large boats, and its banks remain mostly unsettled. (Watch National Geographic video about Africa's Okavango River Delta.)But that doesn't mean it is safe. Some argue that the water that sustains the river's vast wetland would be put to better use by local agricultural operations, diamond mines, or in major cities, such as Pretoria in South Africa.—Tasha Eichenseher

Photograph by David Doubilet, National Geographic