Zanzibar is an insular semi-autonomous region which united with Tanganyika in 1964 to form the United Republic of Tanzania. It is an archipelago in the Indian Ocean, 25–50 km (16–31 mi) off the coast of the African mainland, and consists of many small islands and two large ones: Unguja and Pemba Island. The capital is Zanzibar City, located on the island of Unguja. Its historic centre, Stone Town, is a World Heritage Site.

Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to the south; Zambia to the southwest; and Rwanda, Burundi, and the Democratic Republic of the Congo to the west. Mount Kilimanjaro, Africa's highest mountain, is in northeastern Tanzania. According to the 2022 national census, Tanzania has a population of nearly 62 million, making it the most populous country located entirely south of the equator.