Mount Saint Peter, Sint-Pietersberg in Dutch, is the northern part of a plateau running between the valleys of the Geer to the west and the Meuse to the east. It stretches from Maastricht in the Netherlands through Riemst in Belgian Limburg almost to Liège, so it defines the topography of a border area shared between Flanders, Wallonia and the Netherlands. The name, like the nearby village, church and fortress of Sint Pieter, refers to Saint Peter.
Underground, the interest is the limestone and the flint nodules in it. That combination, plus the position, made this hill worth quarrying for a very long time, and the result is an enormous man-made cave system cut by centuries of marl extraction rather than dissolved by water.
The hill has been altered above ground too. Since the 1930s the Albert Canal has divided it in two. Near the Liège Province village of Lanaye the canal cuts straight through the ridge for 1,300 metres and 65 metres deep, and the Lanaye locks at the eastern end let boats pass from the upper Meuse and the Albert Canal down to the lower Meuse and the Rhine basin. East of the locks the Meuse has since shifted its course, leaving backwaters and old channels behind.
That cut is a useful thing to stand and look at: a hill that took millions of years to form, sliced open to 65 metres in the 1930s so barges could get through.
Guided tours go into the tunnels from Maastricht. They are cold, dark and easy to get lost in, which is why nobody is allowed in unaccompanied.
Netherlands
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