Final answer:
Tanganyika and Zanzibar merged in 1964 to form the country of Tanzania. Tanganyika was a mainland region under British occupation, and Zanzibar was a historic island trading post. The union created a nation that maintains significant cultural and economic importance in the region.
Step-by-step explanation:
The two territories that merged in 1964 to become Tanzania were Tanganyika and Zanzibar. During British occupation, the mainland region was known as Tanganyika, which achieved independence in 1960. Zanzibar, an island off the coast of East Africa known for its spice trade, and Tanganyika combined to form the United Republic of Tanzania. Zanzibar remains a prominent tourist destination, while Dar es Salaam on the mainland is the primate city and major hub of the country.