Fleckenstein castle was built in the 12C as part of the defences of the northern border of the duchy of Alsace. The fortified walls, gateway and an impressive Gothic square tower are still visible. Inside, the staircases hewn out of rock lead to several rooms, including the amazing Salle des Chevaliers with its central monolithic pillar. Higher up is a platform where the seigniorial residence stood, commanding a fine view of the Sauer Valley.