Marks in Stone: The Louvre's Underground Moat

The Louvre started out as a fortress, and where you're standing right now is proof of it. This space was uncovered by accident, while workers were digging underground to build the glass pyramid — what they found were the remains of a moat that once encircled the medieval fortress. It hasn't been restored; it's displayed exactly as it looked the day it was discovered.

Look closely at the walls and you'll spot small marks carved into individual stones — hooks, squares, hearts, and other shapes. These were left by the stonemasons who worked here, marking how much they were owed for their labor. Medieval Europe had craft guilds, associations of skilled workers in a given trade, and masons carved these personal or guild symbols into their stones so that payments could later be tallied up based on who had carved what.

Marks like these turn up not just at the Louvre but on other medieval buildings across Europe, so it's worth keeping an eye out for them on your future travels too.