Not exactly a museum, although inside we find important works and exhibitions. This is perhaps the most important structure in the whole valley, or at least the most iconic. Founded by the noble family of the Guidi Counts, Poppi Castle is mentioned in documents as early as 1191. Its courtyard is a triumphant display of coats of arms, while the intertwining stone stairs takes us almost inside an Escher work. Don't miss the library, with its 25,000 historic volumes, the colorful ballroom and the chapel with frescoes by Taddeo Gaddi, a pupil of Giotto. If you're not easily tired, you can also climb to the top of the tower, you will be rewarded by an absolutely breathtaking panoramic view!