Situated on a 37m high hill, this WWII German bunker, on one of the highest tops in the dunes, was used as observation bunker, overseeing the area to all sides. This bunker was part of a large number of bunkers, together forming part of the Stuetzpunkt Gruppe Katwijk. The bunker is not accessible anymore, but the view from this hill top is still great.
Several kilometers south of here there is also an antitank wall to be found still.
More info: http://www.katwijkinoorlog.nl/atlantikwall/widerstandsnest-251 (Dutch)