The master tower of the castle of Guédelon built in the Yonne department spreads over four levels. The first level is a basement that houses a cellar with a cistern, wall niches, and an archer opening. The second level corresponds to the ground floor. It contains a large firing chamber intended for the protection of the castle and surmounted by a cross-ribbed vault. On the third level, or first floor, is the chamber of the lord, or camera, with walls decorated with murals.