One of the world's most notable feats of architecture is the Colosseum in Rome. Opened in 80 CE by Emperor Titus, this massive structure existed solely to entertain the masses with gladiator fights, animal skirmishes, and, at some point, miniature naval conflicts. While it only took the Romans less than a decade to construct the Colosseum, careful calculation and planning were required. Architects and workers put extensive thought into every detail, from the amphitheater's architectural symmetry to its complex underground maze of corridors and capstans.
For centuries, we have tried to imagine what occurred in the Colosseum, fleshing out a gory fantasy in film and media. For instance, the movie Gladiator, for all its inaccuracies, attempts to create an image of how Romans lived and fought. What we don't see is the grueling work - typically done by enslaved people - it took to put on one of the Colosseum's gruesome shows. Like sex in Ancient Rome, gladiator fights were about power, both of the Roman empire and of individuals. The complexity and grandiosity of the Colosseum's construction helped to assert that power all the more.
In Rome, the ideal ratio was considered 5:3, which is why the arena measured 280 x 168 Roman feet. The measure of a Roman foot varied, but it was around 11.5 inches. The width of the auditorium and arena were equal to the height of the Colosseum. The design was based on multiples of 20 Roman feet.
The size of each arch was also 20 Roman feet, and every arch was separated by three Roman feet. The perimeter of the amphitheater had to be exact because of the Colosseum's arches: there were 80 entrance arches, each of which had to be the same size with the same amount of space in between.
Below the Colosseum is the hypogeum, which is the Greek word for "underground." In the hypogeum are carved sections of wall - it took historians years to decipher their purpose. For instance, architect Heinz-Jürgen Beste discovered tracks in the wall, likely used to transport animal cages through the hypogeum's pathways. Diagonal indentations indicated the placement of ramps that allowed animals to enter the arena.
Beste also determined a series of semicircular cuts in the wall allowed for the placement of capstans, which had four rotating arms used to raise a cage containing an animal from underground into the arena. Beste determined the locations of 60 capstans, 40 of which were used to hoist animals onto the stage, and 20 of which were used to set up scenery.
The Colosseum was able to fill with a few feet of water, on which sailors held mock naval skirmishes in miniature boats.
In order to create this contained aquatic arena, workers at the Colosseum removed the amphitheater floors and wooden supports. An aqueduct was responsible for flooding the arena, and runoff canals helped drain the Colosseum when the fight was over.
The amphitheater didn't have a basement at its opening in 80 CE - the construction of masonry walls, which replaced the wooden supports, ended the possibility of flooding and therefore naval shows in the arena.
Classicist Norma Goldman and engineer Owain Roberts answered questions about the Colosseum for PBS. During the Q&A, Goldman estimated 20,000 to 30,000 people were involved in its construction, a large number of them enslaved.
The Romans built a road especially to transport blocks of travertine from the quarries of Albulae near what is now Tivoli. The quarries were around 20 miles away, and each cartload contained 30 to 50 stones. In total, workers transported 240,000 carts full of stones to build the Colosseum.