The Circus of Maxentius is an ancient Roman circus built by the emperor Maxentius between year 306 and 312 AD. It was a part of a complex of buildings on the Via Appia - one of the earliest and strategically most important ancient Roman roads. Games and races were held in honor of Maxentius' son Valerius Romulus, who died in AD 309 and who was buried nearby.
The Circus of Maxentius is the best preserved ancient Roman circus and only the Circus Maximus in Rome was larger than it. Circus was made of concrete faced with opus vittatum (parallel horizontal courses of tuff blocks alternated with bricks). It is 513 meters long and 91 meters wide, and could have some 10,000 people as audience. Its “spina”, the barrier that divides the circus in half and makes for one circular track is constructed to be exactly 1000 Roman feet long, which translates to today's 296 meters, and was cased in marble. As one more tribute to his son, Maxentius placed the Obelisk of Domitian in the center of circus. This obelisk Maxentius brought from the Isaeum.It was covered in hieroglyphs and in time it broke in five pieces. It was restored by Bernini and it now stands at Rome's Piazza Navona. Near the circus was the villa of Maxentius which was connected to the imperial box (so called “pulvinar”). It was connected via a covered portico so an emperor could enter and exit circus without mixing with plebs. Outer walls of circus are not entirely parallel. They make track wider at the start which allowed chariots to spread before reaching the spina. Track is also wider at the turning point. East end of the track has a small triumphal arch. On the southern side of the track is a place for judges' box from where judge has a clear sight of the finishing line.
Games played at circus were intended to be inaugural games but they became funeral games after Maxentius' only son died and was entombed in the nearby mausoleum. Some say that the reason why the circus is in such a good shape even today is because it was not used too much. Maxentius usurped power in 306 but was not recognized by the other emperors. He was defeated in 312 near the Milvian bridge, north of Rome, by Constantine I the Great. Circus is today under the care of the Soprintendenza Archeologica di Roma.