
Romans and tourists from all over the world will then be able to enter what was the stage machine of the largest amphitheater ever built and admire the passages and arches that connected the rooms where gladiators and animals waited, before being catapulted into the arena .
Consisting of a large central passage along the major axis and twelve curvilinear corridors, in the hypogea of the Colosseum there were the freight elevators that allowed the machinery or animals used in the games to get on the arena and which were probably housed in a series of environments service along the perimeter wall. To raise the scenic materials to the surface from the undergrounds, articulated systems with counterweights and inclined planes were used, of which the holes in the paving of the corridors are still visible today.
A gallery, at the end of the corridor along the major axis towards the east, connected the amphitheater with the nearby Ludus Magnus, where gladiators trained while on the opposite side, towards the Forum, another gallery was probably used for the preparation of the scenography of the shows. Under the east gallery there is a hydraulic conduit which, still today, carries a certain amount of water inside the amphitheater and which, probably, was one of the pits one of the conduits coming from the Celio to feed the lake for the residence of Nero.
This flowing water can be felt very well by visiting the basement of the nearby Basilica of San Clemente which is in fact near the Ludus Magnus.

The gladiators were generally slaves, criminals sentenced to death or prisoners of war and began their careers by submitting to the lanista who had the right of life and death over them.The preparation lasted years and the training took place in the Ludus Magnu, connected to the Colosseum via an underground corridor.
The categories of gladiators were: Reziari, Secutores, Mirmilloni, Thracians, Dimachaeri and each category had its own peculiarities, in terms of equipment and allowed shots and its own advantages and disadvantages. The most classic fights confronted: the Reziari against the Mirmilloni or the Thracians against the Secutores.