Constance tower is the only fortification built under Louis IX, in 1241-1249. After 1686, protestants, which inhabited much of the city, were jailed in the fortified towers. Constance tower is 30m high and 22m wide, and is topped by an additional 11m smaller tower. The additional 11m tower on top of Constance tower. Constance tower was accessed through a wooden bridge during the 13th century. Lower room in the Constance tower. Lower room in the Constance tower. Lower room in the Constance tower. Lower room in the Constance tower. Lower room in the Constance tower. Fireplace, 1868. Lower room in the Constance tower. Open-air toilets. Circular passage around the lower room in the Constance tower.The passage is built within the 6m thick wall of the tower. Upper room in the Constance tower. Constance tower was originally surrounded by a castle, which no longer exists. Walls Labels