It is believed that the Florence Baptistery was once a temple dedicated to the Roman God of war Mars, who was also an agricultural guardian. The baptistery has an octagonal shape that was common for buildings of its kind, as in Christianity, the number eight is considered as a symbol of regeneration. Inside the building, the ceiling is decorated with gold mosaic depicting various levels of Paradise and Hell. The famous Italian poet Dante was baptized here in this very space. Outside, there are three sets of bronze double doors transformed into art. The East Door is the one to pay special attention to, dubbed the "Gates of Paradise" by Michelangelo himself, and was a key element in the Dan Brown novel-turned-movie Inferno.