The archaeological treasure under the courthouse in Luxembourg is open to the public

One of the most mysterious corners of old Luxembourg, the archaeological crypt on the Saint-Esprit plateau, will be accessible to the public for the first time. Minister of Culture and Tourism Eric Thill announced the opening on 3 June as part of the celebrations marking the 30th anniversary of the inscription of Luxembourg's "Old Quarters and Fortifications" on the UNESCO list. Entry will be temporary, as part of the LUGA 2025 exhibition, but authorities are preparing a major renovation.

The first discoveries at the site of the crypt were made in 1996, when archaeological surveys were carried out prior to the construction of the Cité judiciaire. They uncovered the remains of a Clarissine convent founded in 1234 by Countess Ermesinde. From 2001 to 2003, extensive excavations were carried out, revealing the outstanding preservation of the medieval and military buildings. To protect them during construction, the ruins were covered with layers of sand and debris - for 20 years.

In 2023, work began on their excavation. Archaeologists from the National Institute of Architectural Heritage (INPA) and the National Institute for Archaeological Research (INRA) removed 3,000 m³ of rubble. The walls of the monastery and elements of the Saint-Esprit fortress, part of the defence system of the old town, previously thought to have been lost, reappeared beneath a layer of rubble.

For now, the facility is open temporarily, but plans are grandiose: by 2026, a two-year project to create a full-fledged museum route will begin. Five design offices have already been selected, of which one will be finally appointed for realisation. Teisen & Giesler is responsible for the architecture.

While preparations are underway, the public is being offered a preview: during the Luxembourg Urban Garden 2025 exhibition, guided tours will take place on Saturdays at 11:00, starting on 14 June. Visitors will be able to walk along a special platform and see the scale of the excavations, assess the surviving fragments of the buildings and familiarise themselves with the five concepts for the future museum.

Those interested can register by email: info@inpa.etat.lu or phone (+352) 247-86650. The crypt is open to everyone from historians to simply curious citizens, and each visit promises a unique journey back to the 13th century.