Ciao i miei amici!
First the Ancient Greeks and then later the Romans used a distinctive style with specific methods and rules for the architecture of their temples and public buildings. Later in Great Britain and especially the U.S. (with the influence of Thomas Jefferson), this style was adopted for use in many of our modern public buildings. The missing link was Andrea Palladio. Vicenza, where we were today, is ground zero for Palladio designed and inspired buildings. You should especially checkout the Teatro Olimpico. Simply amazing!
Ciao!