The Dahlak Archipelago has been fished for pearls since Roman times, and its shallow oyster banks still give up a few each year. More than 120 low coral and limestone islands lie scattered across the southern Red Sea off Eritrea — flat relics of old reef platforms, lifted a metre or two clear of the water by tectonic movement that has not stopped, and only three are permanently settled. Fresh water is the one thing missing: on Dahlak Kebir, the largest island, people cut some 360 underground cisterns to catch what little rain falls. Beside them stands a medieval town whose basalt gravestones, carved in angular Kufic script, name the sultans who ruled here from the eleventh century until the Portuguese attacks of 1513 began the sultanate's decline — and the merchants, masons and tailors who lived here when Dahlak linked Aksum to Arabia and the Indian Ocean.
Those same waters hold some of the least-disturbed coral reefs left in the Red Sea, and the bare islands above them are one of the great seabird nurseries on Earth. A survey of Eritrea's islands counted 150,000 breeding pairs: Mojeidi, in the southeast, carries some 12,000 pairs of lesser crested terns, and the white-eyed gull — a bird that lives nowhere but the Red Sea — nests here in about a third of its world numbers. They lay in the cruellest months, when the air sits at 35–40°C. Hawksbill turtles come ashore on the same sand in late May and June, green turtles graze the shallows, and dugongs move through the seagrass. Off Nokra, the coral-crusted wrecks of a Soviet naval base lie where they were abandoned in 1991. Reaching any of it takes a government permit and a hired boat, and only 21 islands are open to visitors — which is exactly why it is still like this.