Mont-Saint-Jean is a small medieval village whose castle, perched on a rocky spur, dominates the Serein valley. You can discover the ramparts and the exterior of the 12th century castle, the 12th and 15th century church, beautiful stone houses from the 15th and 16th centuries, a 15th century manor house, crosses, wash houses, dovecotes, the old hospital from the 12th or 13th century as well as the museum of rural life. Also worth visiting is the archaeological site of the Grange du Mont located near the Thomas cross (578 m), 2 km from the village.