Colosseum Underground

Below the arena were a maze of supports, and walls and rooms that held up huge wooden beams that formed the floor of the colosseum. Over these wooden beams was a layer of sand on which the gladiators fought.
The maze of rooms held the cells for prisoners, enclosures for the beasts and assembly areas for the gladiators waiting their turn to do battle that day. There were also pits were cages for wild animals could be hoisted up into the arena.