Nestled beneath the forecourt of Notre-Dame, the Archaeological Crypt of the Île de la Cité offers a breathtaking journey back through time. Established in the late 1970s after excavations from 1965 to 1972, it unveils over two millennia of Parisian history, from ancient Lutetia to Haussmann-era transformations.

The visit opens with remains of an ancient dock, part of Lutetia’s port, followed by remains of public baths complete with a hypocaust heating system and a fragment of the 4th-century city wall. Visitors then move through medieval foundations, including the Hôtel-Dieu chapel and the foundations of Rue Neuve-Notre-Dame from the 12th century. The journey continues with the 18th-century hospice for foundlings and concludes with traces of Haussmann-era sewers from the 19th century .

Covering nearly 200 m, the immersive layout features models, 3D projections, interactive touchscreens, and engraved maps for an educational yet entertaining experience. Families are catered for with multilingual audio guides, kids’ trails, and workshops .

The ambiance is atmospheric—dimmed lights glint off ancient stones, footsteps echo across medieval flooring, and digital projections evoke a sense of historical discovery. The audience ranges from archaeology buffs to families, students, curious tourists, and those exploring beyond Notre-Dame.

Historical highlight: during excavations, archaeologists unearthed remnants of Saint-Étienne, an earlier cathedral buried since the 7th century—it has been partly integrated into the crypt, charting the island’s spiritual evolution .

Practical info: open Tuesday to Sunday from 10 am–6 pm (last tickets at 5:30 pm; exit by 5:45 pm), closed Mondays, Jan 1, May 1, Dec 25 .
Access via Metro line 4 (Cité or Saint-Michel), RER B/C (Saint-Michel Notre-Dame), buses 21, 24, 27, 38, 47, 85, 96, with nearby Vélib’ stations.
Wheelchair accessible, with wheelchair loans, induction loops, and sign-language guided visits .