Originally the site of the Castle of Lucilinburhuc constructed in 963 AD, the Bock has been home to the fortresses of many armies, but it wasn’t until 1744 that the casemates were enlarged to their current size. Throughout their existence, the tunnels have housed slaughterhouses, bakeries, and living quarters, while in WWII they were used as bomb shelters. The galleries are open to the public from March to October.