The Lamu Museum stands on the waterfront in a fine two-storey Swahili merchant's house from the 1890s. It is the best introduction to the Lamu archipelago's history — there are good displays on Swahili culture, dhow-building, the slave trade and its abolition, and the elaborate brass-and-ivory siwa horn of Lamu, one of the great pieces of pre-colonial East African craft.
Plan an hour or so. The exhibits are old-fashioned but informative, and the building itself, with its carved doors and inner courtyard, is worth the entrance fee on its own.