I have always been impressed with the rotunda of the Missouri State Capitol, based off of such august domes as St. Peter’s Basilica in Rome and other early modern churches such as the Invalides in Paris or San Ignatius, also in Rome.
The Parthenon, and its Amerian proxy, the original dome of the U.S. Capitol, also show their influence.
But the “lower dome” as I call it, alludes its pedigree. It has a certain Baroque architectural feel to it, but I would be curious how it was conceived.
The majestic vestibule also impresses. Remember, no smoking.