Most walking tours hit the same spots. This route covers 2000 years of overlooked history in 3 hours, following the layers of civilization.

Start: Crypte Archéologique under Notre Dame — Actual Roman ruins beneath the cathedral. €7 entry, fascinating foundation stones. You can see the original Roman street grid.

Stop 2: Place Dauphine — Henri IV's planned city, first royal urban development. The triangular shape is intentional geometry based on Renaissance ideals of perfect urban planning.

Stop 3: Conciergerie — Where Marie Antoinette was imprisoned. The medieval hall is incredible, better preserved than Sainte-Chapelle next door. The original royal kitchens are haunting.

Stop 4: Tour Saint-Jacques — Lonely Gothic tower, all that remains of a massive church demolished in 1797. Pascal did barometric experiments here, proving atmospheric pressure changes with altitude.

End: Église Saint-Étienne-du-Mont — Sainte Geneviève's shrine, the only surviving rood screen in Paris. Racine and Pascal are buried here. The architecture spans 300 years of styles.

Total walking: 2km through the heart of medieval Paris, each stop revealing different centuries.