The Bock casemates are the vast underground system of passages and galleries at the Bock promontory and continue to be a major tourist attraction.
Can be visited from March to October from the Rue Sigefroid. The stairs down from the entrance lead to the huge archaeological crypt where wall plates give an overview of the history of the fortifications. More stairs lead down through the dungeons of Siegfried's old castle to the casemates themselves, a series of long tunnels down into the rock parallel to the road above. There are a number of lateral passages as well as chambers and balconies with openings to the north and south. Once emplacements for cannons, today they offer views of the Alzette valley below. The tour includes a visit to the living quarters of Marshal von Bender, the Habsburg officer who, at the age of 82, coordinated resistance to the French siege in 1794–95 which lasted almost eight months. The exit is via the Pont du château onto Rue Sosthène Weiss, once the castle moat.