In 963 Count Siegfried acquired a small castle on the "Bock” rock which was to become the birthplace of the city [and country] of Luxembourg. Over the centuries, formidable defense walls were erected to the west, however, they did not prevent the Burgundians from taking the city by surprise in 1443. Thereafter Luxembourg passed into the hands of foreign rulers for some 4 centuries (Burgundians, Spanish, French, Austrian, Germanic Confederation). Over time, the best defense engineers gradually turned the city into one of the strongest fortresses in the world, the “Gibraltar of the North”, featuring 3 fortified ring walls studded with 24 forts and 16 further powerful works of defense as well as a unique network of some 23 km of underground bunkers that could accommodate not only thousands of soldiers with their equipment and horses, but also workshops, kitchens, bakeries, slaughterhouses etc.
In 1867, the fortress was evacuated and dismantled after the Treaty of London declared Luxembourg “perpetually neutral”. The dismantling took 16 years. The superstructure of the Bock, a most important fortification, was razed to the ground in 1875. However, it was impossible to blow up the casemates without destroying a substantial part of the city. The entrances and main communications routes were merely blocked off such that nowadays some 17 km of galleries - sometimes on several levels - still remain. Huge staircases are sunk up to 40 metres deep into the rock. Needless to say that during the world wars, the casemates were used as shelter and could protect as many as 35 000 people against air raids or shelling.
Hardly surprising then that the fortifications and the historic Old Town enjoy an international reputation. In 1994, they were included on UNESCO's World Heritage List.