During World War. two shelters needed to be constructed for protection from air raids.  These were dug in the solid rock and thus the work was quite hard and time consuming.  The work on the shelter near the Rotunda parvis started in 1940 and was opened for use in 1941 after five months of digging.  It was excavated by 15 skilled workers who worked in day and night shifts.

It is 75 meters long and runs for 7 meters under the main square.  The design consists of simple interconnecting corridors, with multiple entrances/exits and a few cubicles.  One of the cubicles was covered in tiles to keep it as clean as possible. This was used in cases when a woman needed to give birth during an air raid.

There is also a great number of displays representing many local trades, showcasing the tools and equipment that were used in those days.