The Rufiji River flows through Stiegler's Gorge, a narrow chasm five miles long, in the Selous Game Reserve of Southern Tanzania. The gorge was named after a Swiss adventurer who was killed there by an elephant around 1900.The Game Reserve covers 48,000 square kilometres and is one of the largest protected areas in the world. Declared a World Heritage Site in 1982, Selous is arguably one of Africa's most pristine wildernesses.