The Civic Museum is a historical-artistic museum inside the fourteenth-century Castello dei Ventimiglia. Building began in 1317 by Count Francesco I Ventimiglia on the hill of San Pietro d'Ypsigro, hence the nickname "Castello del buon aere", from which Castelbuono took its name. The original architecture has Arab-Norman-Swabian compositional characteristics. The Castle consists of three corner towers and a pre-existing round tower from the Byzantine era (12th century). Inside, a courtyard with a staircase gives access to the two upper floors, within which today we find the permanent exhibitions of urban planning, archaeology, sacred art and modern and contemporary art . Contemporary art exhibitions are regularly hosted on the ground floor. On the second floor, next to the Sacred Art section, is the suggestive Platina Chapel , decorated with stuccos by the brothers Giuseppe and Giacomo Serpotta, executed in 1683, where the relic of the skull of Saint Anne is kept in a silver reliquary (1521), patron saint of Castelbuono, together with the artistic wooden "Coro" (1760), the work of the Castelbuonese sculptor Domenico Coco.
With the main branch of the Ventimiglia family extinct, the Castle was purchased in 1920 by the citizens through a public collection, then donated to the Municipality of Castelbuono which decreed its public use. The structural restoration and the museum preparation intervention, completed in 2011, made it possible to define a museum institution. Today, he is an active cultural producer, engaged in the promotion of the local and Mediterranean historical-artistic heritage, through contemporary languages.