Saga Beach is Bujumbura's city beach, at the northern tip of Lake Tanganyika, and it works two shifts. By day it is pale sand, thatched bars and water warm enough to stay in for hours, with the mountains of Congo across the lake. Tanganyika is the longest freshwater lake in the world and the second deepest, holding about a sixth of the fresh water on the planet. It is old enough to have bred its own fish: some 250 cichlid species, nearly all of them in this one lake, including a few that spend their entire lives inside empty snail shells. In the last hour of light you walk down to the reed fringe where the sand meets the water and face west. That is when the day's hand-paddled canoes come back in, crossing the copper glare as low black shapes before the fishermen haul them up onto the sand.
The boats are cut from single trunks and driven by hand, with no engine and no hurry. Sitting low in one changes the scale of the lake: the shoreline flattens out behind you and the paddle knocks against the hull. Twelve kilometres south, two names and the date 25 XI 1871 are cut into a rock where Livingstone and Stanley slept. That was two weeks after the meeting everyone quotes, on a trip up this shore to settle whether a river ran out of the lake at its top end. They found the Rusizi flowing in. The second shift belongs to the ndagala boats. By day they lie moored in the shallows with their long booms crossed above the hulls and nobody aboard, because these crews work at night. On a dark, moonless night you take a spot on the sand back from the thatched bars and let your eyes adjust. The fleet has hung its lamps over the water to draw the sardines up, and the lights are spread right across the black lake, a second town that was not there at sunset.