Substructures of the Colosseum

You are now in the substructure (hypogeum) of the Colosseum, right underneath the arena. The remains of the substructure reveal a deep and complicated edifice, just as fascinating as the rest of the building above ground. You see three concentric circular passages that surround four straight rows of cells along the long axis of the arena. There are broad passages between the cells. Another ring of cells opens up to the outermost concentric passage. There are subterranean entrances at both ends of both axes of the substructure; the one on the east leads to the Ludus Magnus.

Some of the cells were obviously used as cages for wild animals; others housed the hoists and pulleys that lifted the animals' cages up to the arena to fight in the venationes; and still others were for storing cranes and other machinery used for special effects (see model). Spaced along the walls you can see holes cut in the stone where chains could be fastened.

The floor of the wide central corridor was covered by wooden beams, resembling a railroad, the usage of which remains obscure; these no longer exist but can be seen in this nineteenth-century photograph. Underneath the substructure, there is an extensive drainage and sewer system running along the main lines of the building. To see where you are, look at this navigational plan of the virtual site.