The Baptistery is a perfectly harmonious, vast octagonal space with the baptismal font in the center. The overall structure reflects a classic pattern: if you've happened to visit it, the columns leaning against the walls and the marble finish might remind you of the Pantheon in Rome. Inside you'll find the white marble slabs from Luni and dark green slabs from Prato that create the elegant geometric patterns. In the few areas that aren't covered with marble, you can see how this magnificent building is in fact built with simple and inexpensive bricks!
It is beautiful how the light enters from the loggia at the top and spreads over the dome's golden mosaics, but don't ignore the beautiful inlaid marble floor from the 1200s either, although for conservation reasons its functional parts are protected. On the panel near the door facing the Cathedral, it is possible to see various astrological representations including the twelve zodiac signs.