Constructed from brick and concrete, the Pantheon is a circular building. It measures 142 feet in diameter and has a gigantic dome 142 feet above the floor to its highest point. The roof of the rectangular porch, which extends from the building's entrance, is triangular and supported by eight Corinthian columns. The emphasized interior of the Pantheon is a major characteristic
of the building, which is decorated by marble and lit by an opening in the top of the dome.