Zanzibar, Swahili Unguja, island in the Indian Ocean, lying 22 miles (35 km) off the coast of east-central Africa. In 1964 Unguja, together with Pemba Island and some other smaller islands, joined with Tanganyika on the mainland to form the United Republic of Tanzania. Area 600 square miles (1,554 square km). Pop. (2007 est.) 713,000. Both Unguja and Pemba are believed to have once formed part of the African continent, the separation of Pemba having occurred during the Miocene Epoch (about 23 to 5.3 million years ago) while Zanzibar dates from the Pliocene Epoch (about 5.3 to 2.6 million years ago) or even later.
Various types of limestone form the base of both islands. Raised sands and sandstones also occur, together with varied residual deposits similar to alluvial strata on the adjacent mainland. Extensive weathering of the limestones combined with erosion and earth movements have resulted in a variety of soils including red earths, loams, clays, and sands. Flat areas of coral limestone occur to the east, south, and north of Unguja and on the western islands. In places the coral is overlain by shallow red earth or alluvium.
Two Island of Zanzibar
Unguja Island is one of the most beautiful islands in the world. Also known as Zanzibar island and located off the coast of Tanzania, Unguja’s 643 sq. mile island is known for its white-sand beaches, crystal-clear waters, and lush tropical vegetation in the Zanzibar archipelago. Visitors can enjoy a wide range of activities such as swimming, snorkelling, diving, fishing and kayaking. There are also plenty of restaurants and bars serving up local cuisine.
Still classed as part of the Zanzibar Archipelago, 40km north of the main island of Zanzibar (Unguja), Pemba Island is slightly smaller and much more rural than the more popular Zanzibar holidays on the main island.While Zanzibar is relatively flat, Pemba's hills and escarpments are green and picturesque; coloured by the rich greens of ten types of mangoes and many hundreds of clove trees that have traditionally supported the fortunes of this island of spice.