Apollo 11
The Apollo 11 Moon Landing in 1969 was a Templar plot to recover an Piece of Eden,
the Fifth Apple, which was located on the Moon.
With the mission being a success, the astronauts returned and the Piece of Eden came into the possession of Abstergo Industries. Of course, it was never shown to the public. Information about the event was later discovered by Clay Kaczmarek after he had hacked Abstergo's files, during his time as Animus Subject 16.
He later placed the uncovered information onto the Animus' memory core which was implanted into the Animus 2.0, as the fifth cluster puzzle that Desmond Miles would find during his time in the Animus as Ezio Auditore da Firenze at the Hideout, alongside Lucy Stillman, Shaun Hastings and Rebecca Crane.