- "We have found traces of whatever pulled us towards this place. Whispers. Lights flickering through cracks in the earth. A doorway that is also a puzzle. We must find the solution."
- ―Marcus Junius Brutus regarding the Colosseum Vault.[src]
The Colosseum Vault was an ancient chamber created by the First Civilization, located beneath the Santa Maria Aracoeli, but accessed from a secret entrance beneath the Colosseum. The Vault was created to store an Apple of Eden on an erected pedestal at the center of a large chamber, and also contained a projection of one of the First Civilization members, the "goddess," Juno.
To enter the Vault's central chamber, one needed to speak aloud the number "72". To reach the higher tier where the Piece of Eden could be placed, a correct series of levers needed to be pulled, which were in turn accessed by crossing several thin platforms. After all were activated, a set of stairs would rise up to form an easy path up to the Piece of Eden. The pedestals and levers within the Vault could only be activated by the touch of a descendant of the First Civilization.
Marcus Junius Brutus
While in the Vault, Brutus saw visions of what would happen after Julius Caesar's death, and was inspired by them. He and his fellow Assassins, all of whom were also Senators, would later go on to plot Caesar's downfall within its chambers. Brutus also made a drawing of the Vault, as well as of the pedestal it contained; one of these would later hold one of the Apples of Eden.
Ezio Auditore da Firenze
The next known visitor was Ezio Auditore da Firenze, who once passed the entrance hall while seeking out the scroll hidden within one of the Lairs of Romulus. Upon securing the Apple of Eden, he entered the Vault again in 1506, and left it upon the pedestal.
Upon his entrance, Ezio knew the password to enter, although how he had discovered it is unknown. Some time afterwards, he inscribed the password to the Vault upon the wall of the Villa Auditore's Sanctuary.
The latest known visitors were the Assassin team composed of Desmond Miles, Lucy Stillman, Shaun Hastings, and Rebecca Crane, who had figured out the password from the etching Ezio had left in the Villa Auditore.
While making his way towards the Vault, Desmond met with Juno, who spoke to him four times during his attempt to acquire the Apple of Eden. Out of all the Assassins present, Desmond was the only one able to see and hear her. After Desmond activated the stairs and walked up to the Apple of Eden, symbols began to appear around the Assassin team.
Upon touching the Apple, the others appeared to be frozen in time, and Desmond suddenly lost physical control of his body. Juno then took over his actions and influenced him into stabbing Lucy in the abdomen with his Hidden Blade, after which both Desmond and Lucy collapsed to the floor.
- Shaun remarked on two of the symbols that appeared when the Apple was activated, the Phrygian cap and the Masonic eye. He began to say "Now those two come together in only one place–" before being frozen.
- The two symbols only appeared together on the "Declaration of the Rights of Man and of the Citizen," which was written during Revolutionary France in August 1789.
- Of the symbols that appeared, the Abstergo Industries logo was one that appeared quite frequently.
- Many of the symbols that were displayed could also be found in the Glyphs and the Cryptic Messages Clay Kaczmarek left behind.
- Shinto Torii
- Eye of Horus
- Eye of Providence
- Inverted pentacle
- Monkey Nazca Line
- Borromean Rings
- Barcode and date
- Three triangles
- Mountain valley
- Mandelbrot set
- Hebrew for Olam Haba, "the world to come"
- Chinese phrase: "One who does not forget what was before is the master of what comes after."
- By using Eagle Vision at the entrance of the Temple of Juno, the symbol of the Lorenz attractor could be seen on the gate of the Vault. This was also present in the messages Clay had left.
- By using Eagle Vision on the platform between the entrance to the Vault and the central platform where the Apple sat, the blue-lined symbol on the floor turned red, showing the correct freerunning path around the central platform.
- The correct levers to be pulled could also be seen with Eagle Vision; the ones pulsing in gold were the correct switches, not the ones steadily illuminated in white.
- The interior architecture and layout of the vault bore striking similarity to the 11,000 year old ancient monolithic site of Göbekli Tepe, situated in the modern-day country of Turkey.
- The triangle that appeared on the Vault's door and in Monteriggioni was the Tetractys, an invention of Pythagoras. It was possible that the Pythagoreans found the Colosseum Vault as well, and created the password "72", seeing that the symbol was considered as a holy and mystical sign.