Waterloopbos

Before computers could model water, the way to design a harbour, a river mouth or a storm barrier was to build a scale model of it and run real water through it, and the Waterloopkundig Laboratorium did that here from 1951 in a wooded valley in the Noordoostpolder chosen because it had the fall and the water supply to drive the models by gravity. About thirty-five models were built at various times - the Delta Works, Rotterdam's Europoort, harbours in Bangkok, Lagos, Istanbul, Vlissingen, IJmuiden - in concrete on the forest floor, at scales where a metre stood for a hundred. Computers made them obsolete and the site closed in the 1990s. It was left rather than cleared, so the models are now overgrown concrete shapes in the woods with trees through them, walked freely, which is a genuinely strange landscape and now a national monument.

The main sights

• Scale harbours in a wood - about thirty-five concrete models overgrown by forest.
• Gravity-driven testing - the valley chosen for the fall to run water through them.
• Ports from around the world - Bangkok, Lagos, Istanbul and the Delta Works modelled.
• Obsolete and left - closed in the 1990s and not cleared away.

When to go

April to October. Half a day.

What to expect

The concrete is broken and slippery in places and the site is only lightly managed - watch your footing. There is little interpretation on the ground; the visitor centre helps. Public transport is poor.

Nearby

Schokland is south-west; Urk is west; Emmeloord is north.

Key facts