The most prominent landmark in Dinan, the castle's keep rises 34 metres above the old town and can be seen from across the river valley. The building is formed by two circular towers joined by a thick curtain wall, with machicolations running around the top — designed to allow defenders to drop things on attackers below. A moat and drawbridge separate the keep from the town's ramparts.
Inside, a local history museum covers Dinan from medieval times through to the Revolution. The collection is modest but well arranged, and the view from the top of the keep over the rooftops and down to the Rance is the real reward for climbing it.