Originally know as the Flavian Amphitheater, the Roman Colosseum was the largest amphitheater in the ancient world; but it was much more than just a theater.
Unlike its contemporaries, it was not dug into a hillside but was freestanding, and had a seating capacity of 50,000 (80,000 with standing room). The Colosseum still stands today, a testament to the engineers who built it.
Construction on the Colosseum began in 70 AD under the Roman Emperor Vespasian. It was built on the site where Nero’s grand palace and lake once stood, a gift to the people of Rome while at the same time erasing the memory of the tyrannical Emperor Nero.
The Colosseum was completed in 80 AD and it was Vespasian’s son, Titus, who opened it with 100 days of games. While most remember it as the host of gladiatorial games, it was also used for wild animal hunts and could even be flooded with water for mock sea battles.
With no hillside to support the structure, the Romans relied on two of their great engineering inventions: concrete and vaulted arches. While arches had already played a major role in the building of aqueducts (some estimates have the arches saving as much as 50 percent of total building material on those same aqueducts), concrete was a relatively new invention. In fact, concrete was so new that Roman engineers really had no idea how long it would last, so they mixed it together carefully with stone.
Another new engineering technique used in building the Colosseum was known as Standardized Parts. Seats and stairs were actually built off-site and the same size, making them interchangeable. They were then brought to the site and fitted together.
The Colosseum itself was 615 feet long and 510 feet wide. It stood 187 feet high and had a base area of 6 acres. It was designed in the classical Greek model of architecture. To keep its spectators comfortable, it had more than 100 drinking fountains and even a retractable roof, for shade.
If you love engineering history like we do, you’ll really like this video documentary slice about the Roman Colosseum from the popular History Channel, Engineering an Empire.