What Have The Romans Ever Done For Us?

[Anomalocaris]

The Roman pantheon was maintained throughout its history because it was gifted to the Roman Catholic Church shortly after the fall of Rome in 476AD.  It was never really abused or plundered, at least not until the Roman Catholic Church decided to melt down all of its bronze fitting to make the canopy for the altar in St. Peter's.

So it had a much easier life than the Parthenon, or most other buildings remaining from the antiquity.

Also, pantheon's concrete roof is hardly economic.   The roof is 21 foot thick and weigh 5000 tons. Modern steel roof would be a fraction of its weight.