There are few places left on earth that might rightfully be called Eden, and the Mahale Mountains is one of them. The mountains soar to 8,000 feet above the clear waters of Lake Tanganyika, which at 420 miles long and 30 miles wide, is a veritable inland sea. The nearest road is almost 100kms away, and that is the most minor of tracks.

Mahale is an evolutionary triumph, where the clock seems to have stopped early, at the right time. For man - part fish, part forest animal - it couldn't be more sublime.

Mahale Mountains is home to some of Africa’s last remaining wild chimpanzees: a population of roughly 800 (only 60 individuals forming what is known as "M group"), habituated to human visitors by a Japanese research project founded in the 1960s. Tracking the chimps of Mahale is a magical experience. The guide's eyes pick out last night's nests - shadowy clumps high in a gallery of trees crowding the sky. Scraps of half-eaten fruit and fresh dung become valuable clues, leading deeper into the forest. Butterflies flit in the dappled sunlight.

And while chimpanzees are the star attraction, the slopes support a diverse forest fauna, including readily observed troops of red colobus, red-tailed and blue monkeys, and a kaleidoscopic array of colourful forest birds.

You can trace the Tongwe people's ancient pilgrimage to the mountain spirits, hiking through the montane rainforest belt – home to an endemic race of Angola colobus monkey - to high grassy ridges chequered with alpine bamboo. Then bathe in the impossibly clear waters of the world’s longest, second-deepest and least-polluted freshwater lake – harbouring an estimated 1,000 fish species - before returning as you came, by boat.