This stunning evidence of the grandeur and gruesomeness of Ancient Rome is a breathtaking sight, especially if approached from the metro stop of the same name. You exit the station and are stopped in your tracks by the sheer size of the amazingly intact structure. After carefully crossing the busy street, start by simply walking around the exterior and peering in. Don't be surprised if you see a number of cats, who make their home among the fallen columns and stones. When it was built in the 1st century A.D., the stadium seated 50,000 people who would watch the gladiators battle wild animals or each other. These gory events would end with the emperor asking the crowd whether or not to kill a defeated gladiator. A thumbs up would mean that he lived, a thumbs down meant death. The decay of the Colosseum has happened as a result of a couple of different forces. Nature has taken its toll, especially the earthquakes that have gradually shaken the building apart. But over the years, the structure was used as a quarry – the Romans gutted it for the marble that was then used on other structures in the city. Today, the floor is gone, revealing the maze of corridors and rooms that held the animals, gladiators and the slaves that worked to produce the spectacle. Tours are offered in English that can give you insights into the intricacies involved.