Fort Niedergrünewald

The walls and grassy hollows in the park on the edge of the plateau, just below the Mudam, are what is left of Fort Niedergrünewald, and they mark the place from which Luxembourg was conquered. In 1684 Vauban set up his batteries on this height to pound the New Gate on the far side of the valley into surrender; once the city was his, he built forts wherever his own guns had stood, so that nobody could do to the French what the French had just done. This was the biggest of them, put up in 1684 and 1685: a redoubt on the lip of the slope, surrounded by its ditch, with a crownwork of bastions in front and, unusually, a wide open space inside where earthworks could be thrown up if the outer walls were lost. It commanded both the plateau and the road up from the Pfaffenthal, and it did the job so well that in the next two centuries almost nothing about it needed changing. In 1733 the Austrians added Fort Olizy a little further out and joined the two by an underground gallery; another gallery ran down to the Vauban barracks in the valley.

The fort was handed over to the civil authorities on the 21st of August 1867 and blown up, in stages, between 1872 and 1876. Unlike its neighbour Obergrünewald, which has largely been rebuilt, only fragments were left here, and the ground became public parkland. But the redoubt in the middle, buried for a century, has been dug out and partly rebuilt, and it is open to anyone: you can walk round the ditch, into a casemate, and along one of the counter-mine galleries — the tunnels the defenders dug outward under the glacis so they could blow up an attacker's tunnels before he reached the walls. On the flank of the left bastion, holding up the slope, sits one of the city's nine surviving Spanish turrets: the one that was painted red, white and blue one night in October 1941.