The international boundary follows the south shore of the pool (roughly 30 km in diameter). The Republic of the Congo, originally a French colony, is sometimes called Congo-Brazzaville - as opposed to the Democratic Republic of the Congo (known from 1971 to 1999 as Zaire) which is often called Congo-Kinshasa, originally a Belgian colony.
Brazzavilles population is less than a tenth of Kinshasas. There is no bridge between the cities so that water craft of many kinds ply between them. It is not uncommon to see dugout canoes being paddled between the cities.