The Natural History Museum occupies the German colonial Boma at the east end of Boma Road, a solid stone building surrounded by gardens where the Via Via bar and traveller hangout has taken root. The museum covers Tanzania's geological formation, its prehistoric wildlife, and — most usefully for visitors about to head on safari — its living fauna. The displays are old-fashioned but informative, and the explanatory panels on East African mammals, birds, and ecosystems are genuinely useful preparation for game-viewing.
The gardens behind the Boma are a good place to spend an hour: tables under shade trees, cold beer, food, and noticeboards where safari companions are found and operator reviews compared. Many independent travellers find their safari groups here rather than through booking offices. Entry to the museum is a few dollars; the gardens are free.