The Pantheon is a beautiful ancient building that was constructed in the honor of Hadrian between 118-128 AD. It was originally a Roman Temple and later during the time period of christian Rome it was used as a church. One feature of the most impressive features of this building is the dome. The dome is massive and it has nothing supporting it other than the walls, in other words there is no steel or iron skeleton to support the dome. At the center of the dome there is an opening looking up at the sky. This is a testament to the engineering of the Romans. This dome that was built so long ago with ancient building techniques is still standing.