Mafia

Mafia appears in the record at least as early as the 8th century, as part of the same Swahili trading world as Kilwa and Zanzibar. It sat conveniently at the mouth of the Rufiji, the river that drains a vast interior, and the ruins on the archipelago — most notably Kua on Juani Island, a substantial Shirazi-era town — show it was never a backwater.

It passed through the usual sequence: Shirazi settlement, the orbit of Kilwa, then of the Omani sultans of Zanzibar. Under an 1890 treaty Germany acquired the island, with part of the mainland coast, from the Sultan of Zanzibar for four million marks, and on 12 January 1915 British forces took it — early in the East African campaign, and useful to them as a base for the air operations against the German cruiser Königsberg, which was hiding up the Rufiji delta a short distance north.

Since then it has been quiet, and that quietness is the whole character of the place. Where Zanzibar built an industry, Mafia did not — partly because access stayed difficult, partly because the reef rather than the beach is the attraction. The name, incidentally, has nothing to do with Sicily; it is usually said to come from the Arabic morfiyeh, an archipelago, or the Swahili mahali pa afya, a healthy place.

The reason most people come is in the water. Whale sharks — the largest fish in the ocean, harmless plankton feeders — gather off Kilindoni Bay on the island's west side to feed, and unusually for the species they are present in numbers and close to the surface. The season runs roughly October to March, with November to February the most reliable window. Swimming with them is snorkelling, not diving, and it is regulated: no touching, limited numbers in the water, no chasing.

The diving in Chole Bay is the other draw — a deep protected anchorage with strong tidal exchange that brings clear water and big fish through the passes. Green turtles nest on the beaches and there is a rehabilitation programme on Juani.

On land, the culture is Swahili and Muslim and quiet. Chole Island, ten minutes across the bay, is the most rewarding walk on the archipelago: a nineteenth-century settlement being swallowed by baobab and fig, with ruined customs houses and a boat-building yard still working. Kua, on Juani, is the older and larger ruin, overgrown and rarely visited.