Archaeological site in Berg en Dal

You're standing on the Duivelsberg, the Devil's Hill, right by the German border near Wyler. In the Middle Ages this was the site of a castle called Mergelp. No stone walls remain, but take a good look at the shape of the ground. The castle consisted of two mottes, man-made mounds with a fortification on top. Those mounds are still here, together with the earth banks around them.