
All the holes that "move" the structure are due to the medieval removal of the metal pins that were used to hold the travertine blocks that covered everything. Inside, then, the structure is divided into segments by some wedges starting from the base: the aforementioned pillars, connected by arches and rampant vaults, supported the cavea. The advantage was in being able to allow more sites to continue independently in the construction of the same structure, practically divided into four main sites and in their own right. Undoubtedly a wonderful example of organization and planning of the work to be carried out. The basement is divided by three concentric walls and the consequent three annular corridors: towards the center the walls become rectilinear and parallel to the central axis, which is also a corridor. The latter extended in two directions, east and west, even outside the structure: the east branch reached one of the most important gladiatorial barracks known, the Ludus Magnus, still visible today at the intersection between via Labicana and via di S. Giovanni in Laterano. Also outside the majestic structure of the Colosseum there are some travertine stones, discovered in 1895, inserted into the pavement also in travertine: concentric with the same building, they were to mark the area of ??respect. According to another interpretation, they were used to board the ropes of the velarium on the ground.