All rests on a strong construction which was particularly impressive for its greatness and also for the efficiency in maintenance and was found on the north west side where the hill falls toward the Aniene valley, creating a marked gradient. The structure had been constructed in alternating layers where each one was articulated by buttresses alternated with arcades, some of which opened into windows. These overwhelming arcades were particularly suggestive to the eye. Under the portico of the temple, situated on the highest part of the complex, the back walls were in a double series in order to put in drainage and also nine arcades were raised so as to overcome the gradient of the steep ground. These nine arcades were laid on 25 unseen arcades and had some windows in the middle so as to allow some illumination on the inside.
are still 23 remaining.
The platform was surrounded by porticos on three sides, giving a U-shape and allowing the side facing Rome without anything. Under this there was a semicircular staircase constructed for a theatrical cavea. In the middle of the platform was, in the end, erected for the shrine. One was able to enter the wide square by two big staircases built on the sides of the theatre.
The square was surrounded by a Doric portico on three sides, which on the inside ran through a corridor covered by a barrel shape vault.
On top of the first must have ran the second portico with inter columns (the space between the columns) which was wider than the one below and colonnade inside, perhaps Ionic, of which there are still traces today on the north east side. The square that welcomed the coming believers to worship and question the god, constituted the centre of the whole sanctuary. The temple was raised at the end square, while on the south east border, taking advantage of the unlevelled ground, the theatre (already mentioned above) was built and still today there are some remains. The temple of Hercules was situated behind the portico. It was a huge peripteros, which was surrounded by a colonnade on all sides except the one in the back.