The original Pantheon was built in 27 B.C. It burned to the ground in 80 A.D. and was rebuilt and dedicated around 125 A.D. The Pantheon is now almost 1900 years old. It is the most well preserved building from ancient Rome. The most significant architectural design of the Pantheon is its dome roof. The interior dimension of the dome is over 141 feet making it the world's largest unreinforced concrete dome. The Roman architects and engineers were ahead of their time with their ability to work with arches, marble, and concrete. If you're traveling through Rome, take some time to visit and appreciate this amazing work.