The Maeslantkering is a storm surge barrier on the imaginary dividing line between the Nieuwe Waterweg waterway located at Hoek van Holland and the river the Scheur located along the cities of Maassluis and Vlaardingen up to the confluence of the rivers Oude Maas and Nieuwe Maas, Netherlands, (51°57′18.98″N4°09′49.63″E), which automatically closes when needed.