Acropolex

According to legend, the Acropolex in Nyon was one of Cybertron's capitals during the Golden Age, but the building was abandoned long before the war broke out and is now in ruins. The interiors are labyrinthine and contain many spiritual elements, such as a chamber resembling the Halls of Order of the Knights of Cybertron and a shrine dedicated to the Matrix of Leadership.

Fiction

2005 IDW continuity

When Zeta Prime began draining Nyon's rebellious population of their energon, he stored the energy in the heart of the Acropolex. The drained citizens often made their way inside in hopes of soaking up any drops of energon that might have been spilled. Wishing to prove to Orion Pax that Zeta was committing crimes against Cybertron, the insurgent Hot Rod lured him and his Autobots to the Acropolex to show him the energon tanks. As they followed Hot Rod through the building, they ran into several impressive sights that got them thinking about the current state of Cybertron, but Orion ignored them and pushed onward until they found their target. Ruins From the Acropolex, Orion Pax saw that Zeta Prime's Omega Destructors were attacking Nyon, and left to distract them while Hot Rod evacuated the city. Purge

Orion Pax was later chosen by the Matrix, becoming Optimus Prime. He journeyed to the ruins of Nyon and discovered that the Acropolex was in fact part of the sleeping Titan Metroplex, whom he awakened. After Metroplex transformed to robot mode, eschewing his disguise, Prime declared that he was no longer the Acropolex. Rise