The Old Boma on Sokoine Drive is the oldest standing building in the city, a single-storey block of coral rag and lime plaster put up by the Sultan of Zanzibar in 1867 as the local administrative seat. The wide verandah and carved Zanzibari door — studded with brass spikes once meant to defeat war elephants — survive almost intact. The Germans later used the building as their first colonial headquarters; the British added the upper floor and the corner balcony.
Inside is a small heritage centre and a café run by the Dar es Salaam Centre for Architectural Heritage. Their walking tours of the colonial core, leaving from here on Saturday mornings, are the best two-hour introduction to the old city's architecture.