The Colosseum is one of the oldest and most famous landmarks in Rome. The ancient Romans were great builders. The Colosseum was built of concrete, faced with stone, as were most amphitheaters. It was built in the early days of the Roman Empire, around 70 CE and it was built in only 9 years. The Colosseum is huge, an ellipse 188m long and 156 wide. Originally 240 masts were attached to stone corbels on the 4th level. 55,000 people could be seated inside the Colosseum. All 55,000 people could be seated in only 20 minutes. Over 400,000 people died in the Colosseum in the 390 years it was open for entertainment.