Most of the architectural designs of Roman buildings were inspired by the ancient Romans and their famous inlays in education, infrastructure and culture. This is proof in the Castle Sant’ Angelo in Rome. Constructed for the mausoleum for the Emperor Hadrian, this circular building is accessed via Benini’s Port Sant’ Angelo bridge. The now converted museum is—was—converted into a papal fortress in the 6th century and is linked to the Vatican by underground passages. The other bit of trivia linked to this castle’s rich history: Puccini’s Tosca leapt to her death from the topmost tier of the fortress.

You can’t visit the spectacular architecture of Rome without having visited St. Peter’s Square in the Vatican City. This country has its own currency, postal address, area code and rules of diplomacy, all for access to one important man: the pope for the Catholic arm of Christianity. It’s in this country in Italy where the Sistine Chapel displayed Michaelangelo’s finest work and other priceless art treasures—to make up for lack of natural beauty in that country, though nothing could replace that.

You simply cannot visit Rome without seeing the famous and aging Roman Colosseum. This distinctive piece of historic architecture was first constructed in 80 A.D. and was meant as an amphitheater for large productions and grand spectacles like gladiator fights—and to control the massive crowds to see these things—was a monumental feat for the ancient Romans.

What would see Rome be if the Leaning Tower of Pisa was missed? This piece of amazing Roman history and architecture is actually the bell tower of the Pisa’s Cathedral Square and was first constructed in August, 1173. Recent times found the tower leaning too far over, so weights were placed on the tower’s non-leaning side to counterbalance this time-pressured slide. And, though the architecture was of the finest quality in limestone, pyrite and slab, the building’s foundations were perpetually too soft on the site’s one side—so the inclination was built into the actual edifice.