Africa's Okavango River Basin, which covers 125,000 square miles across Angola, Botswana and Namibia, is home to the largest remaining population of African elephants as well as significant populations of lions, cheetahs, wild dogs and hundreds of species of birds. It's also a vital source of water for more than 1 million people and feeds Botswana's majestic Okavango Delta, a World Heritage Site that is now threatened by human activity along the rivers that feed it. In 2015 National Geographic Fellow Dr. Steve Boyes assembled a remarkable team to embark on a four-year project to study this vast and diverse ecosystem to determine how best to protect the delta and its headwaters for generations to come. The first 1,500-mile river expedition of the project brought together local guides and international explorers, storytellers and scientists. The team included 27-year- old marine biologist Adjany Costa, who grew up in the sprawling Angolan capital of Luanda during the country's brutal civil war, as well as an Okavango native, Tumeletso Setlabosha, nicknamed "Water," an expert boatsman who spent his entire life on the delta. Starting in Angola at the source of the Cuito River, one of the three arteries feeding the basin, the explorers traveled by traditional canoe (mokoro), but they soon ran aground when the stream narrowed to a trickle, forcing them to drag their boats across marshland for eight grueling days. As the river again became navigable, the team's hopes of documenting a thriving ecosystem were further deterred when they encountered vast tracts of woodland burned by local hunters. Despite these initial disappointments and setbacks, Boyes and his team continued their journey through the highlands of Angola and soon encountered a dizzying array of wildlife. By journey's end, the scientists collected data from 50,000 locations along the way, chronicling dozens of new scientific discoveries and shedding fresh light on the delicate interconnections that bind humankind with nature. Directed by National Geographic Society filmmaker Neil Gelinas and featuring stunning wildlife photography and aerial views of rarely seen vistas, National Geographic Documentary Films' Into the Okavango is a deeply moving chronicle of modern-day explorers forever transformed by the adventure of a lifetime. It is also an attempt to draw the world's attention not only to the Okavango River Basin, one of the most important areas for biodiversity conservation, but to the little-known and vulnerable wilderness area in the Angolan highlands on which it depends.