Grand Temple

"Each Vault's knowledge was transmitted to a single place."

- Jupiter speaking of the Grand Temple

The Grand Temple, or the Central Vault, was created by the beings of the First Civilization. Its location was in North America, around modern upstate New York. Like the other temples across the planet, its purpose was to create different methods of saving and preserving the world, and was the location where Jupiter, Minerva and Juno collected and tested the discoveries of the other temples, in the hope of finding the most effective methods of the Earth's salvation from the incoming solar flare.

Like the other Vaults, the Grand Temple was buried underground in order to protect its contents from the war with humanity and the solar flare, and was hidden beneath a statue dedicated to the Capitoline Triad. However, the statue was destroyed in the First Disaster, and its location remained hidden until Desmond Miles' revelation.

History
Before and after the war with humanity, all information from the other temples regarding any way to prevent the first catastrophe was sent there for Jupiter, Juno, and Minerva to "sort and sample all that was collected." The three tested six possible solutions in succession, "each more encouraging than the last," but all six solutions ultimately failed.

Following this, the solar flare destroyed most of the First Civilization, and less than 10,000 humans survived. However, the two groups worked together, beginning around the remains of the Grand Temple. The members of the First Civilization attempted to pass on their gifts to humans through crossbreeding, resulting in some individuals being able to access Eagle Vision and use the Pieces of Eden. As time went on, the memories of the First Civilization, the location of the Grand Temple, and the disaster itself dissolved into other cultures and were ultimately forgotten.

However, Jupiter, Juno, and Minerva created a plan for the planet's salvation for 2012, where they believed a similar disaster to that which killed their people would occur again. In 1499, Minerva spoke to the Assassin Ezio Auditore da Firenze, a descendant of the First Civilization, in the Vatican Vault. Unbeknownst to Ezio, his memories would be viewed by his descendant Desmond Miles in 2012 via the Animus. Minerva spoke directly to Desmond through Ezio, telling Desmond about her people, the war with humanity, the disaster, and their efforts to rebuild the world. She warned Desmond to act quickly, and to beware of the Templars.

In 1506, Ezio Auditore and Leonardo da Vinci discovered a smaller vault in Rome. Unlike the Vatican Vault, the Pythagorean Vault contained a set of coordinates: 43 39 19 N 75 27 42 W. Leonardo was baffled by the information, but Ezio inherently understood that these numbers were intended for Desmond. William Miles, Desmond's father and the de facto Mentor of the Assassin Order, noted these memories outside the Animus, and set out to these coordinates, which he believed to be the location of another temple.

In 1511, Prince Ahmet, the Templar leader in Constantinople, desired the location of the Grand Temple in order to end the differences between men, and create a unified world. He believed that the legendary Assassin Altaïr Ibn-La'Ahad discovered the temple's location, and that he had hidden that knowledge in his library beneath Masyaf. With this belief, he organized an excavation to find the library, which Ezio Auditore ultimately discovered. From 1511 to 1512, Ezio stayed in Constantinople to recover the keys to Altaïr's library, which subsequently led to him opening it. However, the library was empty, except for Altaïr's remains, a sixth key, and Altaïr's Apple of Eden.

Weary of his life as an Assassin, Ezio chose not to take the Apple from the library. However, the Apple began to glow, and Ezio began to speak directly to Desmond as Minerva had. Ezio asked Desmond to make sense of the questions that had plagued him, and to make the suffering he had endured worth something. Desmond's image then appeared through the Apple, and Ezio sent him into a Synch Nexus.

There, Jupiter spoke to Desmond. He further explained and elaborated on what had happened to him and the rest of the First Civilization, and he charged Desmond with the task of going to the Grand Temple, as that would help him find a means to save the world from the next solar flare.

With the message complete, Desmond woke up from his coma, surrounded by Shaun Hastings, Rebecca Crane, and his father, William, inside a van. Desmond told the others that he knew what needed to be done, and William opened the car door to reveal they were in a field where the Grand Temple once stood.