In two years, Luxembourg City will get a further protected UNESCO site when the medieval crypt under Saint-Esprit opens.

The archaeological crypt was part of the Klarissinen monastery, built on plateau du Saint-Esprit in the 13th century. French engineer Sébastien Le Prestre de Vauban later converted the site for military purposes. The impressive underground structure was only discovered in the 90s, when the current Cité Judiciaire was built. It was filled with sand in 2002 to protect it during the building works.

Currently, the crypt is being converted so that from 2024 visitors can learn about architecture and daily life inside a monastery, the life of women during the middle ages, and the history of the fortress. A 200 meter pedestrian bridge will provide access to the 1,000 square meter structure.

The first step will involve removing the 3,000 cubic meters of sand which currently fill the crypt. Sam Tanson, minister for culture, visited the site on Tuesday and called it "an archaeological treasure".