The sources of the Congo are in the Albertine Rift Mountains that flank the western branch of the East African Rift, as well as Lake Tanganyika and Lake Mweru. The river flows generally west from Kisangani just below Boyoma Falls, then gradually bends southwest, passing by Mbandaka, joining with the Ubangi River, and running into the Pool Malebo (Stanley Pool). Kinshasa and Brazzaville are on opposite sides of the river at the Pool. Then the river narrows and falls through a number of cataracts in deep canyons, collectively known as the Livingstone Falls, and runs past Boma into the Atlantic Ocean. The river also has the second-largest flow and the second-largest watershed of any river in the world (trailing the Amazon in both respects). The river and a  wide strip of coastline on its north bank provide the country's only outlet to the Atlantic. 