The Congo River -- formerly called the Zaire River -- is Africa's most powerful river and the second most voluminous river in the world with a discharge of 1,500,000 cubic feet of water per second. It is the second longest river in Africa after the Nile and ninth longest river in the world, draining a basin of nearly 4 million square kilometers (1.5 million square miles), or 13% of Africa's landmass.
The river is arguably best known for its role in history. Called "the heart of darkness" by Joseph Conrad, the river and surrounding rainforest have long been thought of as the mysterious land of pygmies, mythical beasts, dreadful plagues, and cannibals. It is a region made famous by the travels of Stanley and Livingstone, and known as a place of brutality and violence for its past: the days of the Arab slave and ivory trade, its long history of tribal warfare; colonial abuses; and its volatile present.
The river itself is as turbulent as its history, though it begins peacefully enough in the savannas just south of Lake Tanganyika. Gradually the river widens and picks up speed until it enters the "Gates of Hell," a 75-miles long canyon of impassable rapids. The river emerges again, surrounded by lush tropical rainforest as the Lualaba or Upper Congo. During the course its journey through the rainforest, the river crosses the equator twice. Because the watershed of the Congo drains from both the Northern and Southern Hemisphere it does not have the seasonal fluctuations in water level that characterize other great rivers. The Upper Congo abruptly ends with Stanley Falls, a 60 mile stretch of rapids.
Stanley Falls gives way to the Middle Congo, a 1000 mile stretch of navigable river, nine miles wide in some parts. Along this quiet stretch of river is the city of Kinsangani, a city known for conflict since Belgian colonial days. Near the end of the Middle Congo, the river slows to a virtual stand-still for 20 miles, a section known as Stanley or Malebo Pool. Here the river is 15 miles wide and flanked by the capital cities of Kinshasa and Brazzaville. The peace of the pool is suddenly shattered by Livingstone Falls, 220 miles of rapids and cataracts. There are some 32 cataracts. The final 100 miles to the Atlantic ocean from the end of the falls is fully navigable.