Zanzibar is a semi-autonomous Tanzanian archipelago in the Indian Ocean, best known for Stone Town (a UNESCO World Heritage Site since 2000), the postcard beaches of Nungwi, Kendwa, Paje and Jambiani, spice plantations dating to the 1800s Omani sultanate, and world-class snorkelling at Mnemba Atoll and Chumbe Island.
The layered culture is what makes Zanzibar stick — Swahili, Omani-Arab, Portuguese and Indian influences all sit inside one small archipelago. You get Stone Town's carved wooden doors, spice tours through the interior, dhows at sunset off Nungwi, and full-moon parties at Kendwa Rocks — often in the same trip.
Most travellers spend 5–7 days on Zanzibar: 2 nights in Stone Town for the culture, then 3–4 nights on a beach (Nungwi/Kendwa for lively; Paje/Jambiani for quieter). It works as either a standalone island escape or the tail end of a mainland Tanzania safari.