Zanzibar (from Arabic: Zanjibar, from Persian: Zangibar'Coast of Blacks'; zangi [black-skinned + bar [coast) is a semi-autonomous part of Tanzania in East Africa. 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 numerous small islands and two large ones: Unguja (the main island, referred to informally as Zanzibar), and Pemba. The capital of Zanzibar, located on the island of Unguja, is Zanzibar City. Its historic centre, known as Stone Town, is a World Heritage Site and is claimed to be the only functioning ancient town in East Africa. Zanzibar's main industries are spices, raffia, and tourism. In particular, the islands produce cloves, nutmeg, cinnamon, and black pepper. For this reason, the islands, together with Tanzania's Mafia Island, are sometimes called the Spice Islands (a term also associated with the Maluku Islands in Indonesia).