The gladiatorial circle in Zagarolo is a small amphitheatre, used as a training gym for gladiators.
The elliptically shaped building was made out of cement and opus reticolatum panelling around the 1st C. A.D.
The original construction clearly contained two concentric walls.
Now a large part of the hemicycle is still standing along with two niches for the saluting stand, while the presence of holes would seem to suggest that the bleachers were made of wood.
Above the niches and above certain openings in the wall one can make out a relieving arch made out of bricks arranged on their side in a fan configuration.
There is no doubt that certain parts of the wall have been completed in post-Roman times with a variety of materials, all bound with mortar.
The building is located on the Pero Hill, two kilometres away from the centre of Zagarolo.