The Natural History Museum of Maranhão occupies a colonial building in the historic centre and documents the natural environment of the state — the mangroves, the cerrado scrubland, the Amazon-influenced forest to the southwest, and the unusual transition zone where the Lençóis Maranhenses dunes meet the coast.
The collection is modest but well-presented, and the exhibits on the Lençóis Maranhenses ecosystem are particularly good — explaining how the famous turquoise lagoons form, what lives in them, and why they appear and disappear seasonally. A useful visit before a trip to the Lençóis.