Provins has many underground passageways (the ones you can see were dug out of a layer of tufa that appears at the base of the spur supporting the upper town). Upon entering theses passages via a low-vaulted room that was part of the old Hôtel-Dieu, look out for the historical graffiti (15C-19C) on the walls. Here, you can also learn about the different uses of these galleries - as a cellar, place of refuge, a meeting-place for freemasons etc.