Housed in an 18th-century mill on the northwest edge of town, this enthusiastic, well-curated little museum explores the prehistoric talayotic civilisation of Mallorca. Many exhibits are from the nearby Son Fornés talayot (watchtower), inhabited from around 900 BCE to the 4th century CE. One of Mallorca's most important archaeological sites, the talayot is easy enough to visit: head 2.5km northwest out of Montuïri on the Ma3200 towards Pina and you'll see it to the right (east) of the road.
Free three-hour guided tours of the museum, talayot and mill can be booked by calling ahead (times are listed on the website).