This is at the southern end of stone town, near the junction of creek road and kaunda road in the area called Mnazi Moja. It is also known by its local title: Beit El Amani (House of Peace). With its distinctive dome, arabesque windows and whitewashed walls, the building looks like a mosque or basilica church. It was designed by the British architect J H Sinclair, who also designed the high court, the British residency and several other public buildings around Zanzibar town.

'Museum' is a misnomer nowadays, as virtually all its viewable exhibits have been shifted to the rapidly developing museum in the House of Wonders and the place now serves as a library. Its well-known giant tortoises have been transferred to Prison Island.