The Maeslantkering is one of the largest moving structures on earth, and it sits quietly on the Nieuwe Waterweg, the channel that brings the sea to Rotterdam, in the town of Hoek van Holland. It consists of two enormous white steel arms, each about two hundred metres long, which rest in dry docks on either bank. When a severe storm surge threatens, the arms swing out, float across the channel, and sink to seal it, all by computer, without a human hand. Opened in 1997, it is the last big piece of the Delta Works, the vast series of dams, barriers and sluices that the Dutch built after the North Sea flood of 1953 drowned much of the south-west and killed more than eighteen hundred people.
You can see the whole thing from the outside, and there is a small visitor centre, the Keringhuis, where displays explain how it works and why. The arms look from the road a bit like the wings of a giant, unlikely bird. The barrier is tested once a year, usually before the storm season, though it has rarely been closed for real. It is a reminder that a country where a good third of the land lies below sea level lives with water as a daily fact.
For a rider, the roads around here are flat and wide, with industrial views and long open bends along the dyke. Wind is the main character, and gusts of side wind on the exposed stretches by the water deserve respect. Heavy lorries serve the port, the roads are busy on weekdays, and many junctions have bike lanes you need to watch. Weekends are quieter and more pleasant.
Hoek van Holland is a seaside town, a ferry port with service to Harwich in England, a beach and a few simple places to eat fish. It has fuel, and Maassluis and Rotterdam are close for more. The town is a good place for a coffee on the front, watching ships go in and out of one of the busiest ports in Europe. In clear weather the horizon is full of tankers and container ships in a line, which is a remarkable sight for those who like moving machinery.