Lake Tanganyika is the second deepest and, by volume, the second largest lake in the world (after Siberia's Lake Baikal in both respects). It lies in four countries' territories: a little in each of Burundi and Zambia, and more than 40 percent in each of the Democratic Republic of Congo and Tanzania.
Part of the Great Rift Valley, Lake Tanganyika is about three million years old and is fed by at least 50 streams and rivers. Its isolation and age have conspired to make it one of the most biologically rich and scientifically valuable habitats in the world. Holding 8% of the world's freshwater, Lake Tanganyika is home to no fewer than 500 fish species. However, its great depth means there's little oxygen in its deep waters and nearly all of Lake Tanganyika's fish stay within 20 metres of its warm, well oxygenated surface.
The main settlement on the lakeshore is the town of Kigoma. Visitors come here because it is the jumping off point for Tanzania's two superb rainforest reserves that border the lake: the incredibly beautiful Mahale Mountains National Park and the equally enticing Gombe Stream National Park.
Both parks are famous for their populations of habituated chimpanzees as well as a wide range of other primates, forest birds and dazzling clouds of butterflies. There is accommodation in each park, including a sensational lakeside lodge in Mahale. These remote reserves are not as easy to accesss as Tanzania's more famous safari destinations but both offer visitors a rewarding insight into the biodiversity of a famously biologically rich region.
There's accommodation on the 52-hectare Lupita Island as well, set in the southern part of Lake Tanganyika. Visitors can choose between water activities such as diving, snorkelling and sailing as well as land-based adventures such as hiking and excursions to local fishing villages. Also in the area is Katavi National Park, long considered one of Tanzania's best-kept safari secrets. Combine a traditional big game safari in Katavi with a stay in Mahale or Gombe for a unique savannah and rainforest adventure.