It is composed of the Zanzibar Archipelago in the Indian Ocean, 25–50 kilometres (16–31 mi) off the coast of the mainland, and consists of many small islands and two large ones: Unguja (the main island, referred to informally as Zanzibar) and Pemba Island. The capital is Zanzibar City, located on the island of Unguja. Its historic centre, Stone Town, is a World Heritage Site.
