The arena itself was 83 meters by 48 meters (272 ft by 157 ft / 280 by 163 Roman feet). It comprised a wooden floor covered by sand (the Latin word for sand is harena or arena), covering an elaborate underground structure called the hypogeum (literally meaning "underground ''). The hypogeum was not part of the original construction but was ordered to be built by Emperor Domitian. Little now remains of the original arena floor, but the hypogeum is still clearly visible. It consisted of a two - level subterranean network of tunnels and cages beneath the arena where gladiators and animals were held before contests began. Eighty vertical shafts provided instant access to the arena for caged animals and scenery pieces concealed underneath; larger hinged platforms, called hegmata, provided access for elephants and the like. It was restructured on numerous occasions; at least twelve different phases of construction can be seen.
what is on the floor of the colosseum
sand sand