Address pantheon, rome Map, Tel 06/68300230 Call, Hours Mon-Sat 9-6:30
The Pantheon, designed around 120 AD is beautiful in its symmetry. The diameter of the dome is equal to the height of the walls. Kids will be fascinated by the open "window" hole at the top of the dome (and the holes in the marble floor designed to allow the rain that comes in through the hole to flow out).
The Pantheon gets quite crowded, so try to visit in the morning.