COLOSSEUM, Exterior
An ancient prophecy of almost 1500 years ago says, "As long as the Colosseum exists, Rome will also exist, when the Colosseum collapses, Rome will fall, and when Rome falls, the world will fall". So let me begin to tell you about the Colosseum from its exterior. This legendary monument that marks many firsts in history, is above all the largest amphitheater in the world. Unlike most amphitheaters, however, it isn't built on a sloping surface, and has a perfectly autonomous structure that can entirely support itself.
First of all, let me immediately correct a popular misunderstanding: the Colosseum is not round! It is oval-shaped, and measures 188 meters at its greatest length and 156 meters at its smallest length, and 57 meters in height. Its designer's name isn't certain, but historians suppose that it's the same architect who built Domitian's Palace on Palatine Hill.
The external structure is completely in travertine, a clear limestone rock that's typical of Lazio; you'll see it used in many Roman monuments. It is divided into four levels: the first three are made up of eighty arches divided by pillars, with half-columns that follow the classical architectural orders, namely Doric, Ionic, and Corinthian. The fourth floor lacks arches and is decorated with columns that just barely protrude from the wall, and small windows. The arches of the second and third levels were decorated with marble statues, which as you can imagine have been stolen over time, like the rest of the decorations.
FUN FACT: in 1200, a palace was built inside the Colosseum that was inhabited by the Roman Frangipane family. Then it continued to be inhabited up to the 1800s!
In the Fascist era, they even got so far as to plan to transform the Colosseum into a luxury hotel: fortunately they never did!