The Colosseum is definitely not the only Roman amphitheater in existence. Other amphitheaters were constructed throughout the Roman world. The remains of at least 230 amphitheaters have been found in almost every part of the Roman Empire. Outside of Rome, well preserved amphitheaters can be found in Pula, Croatia and Nimes, France.
The first Roman amphitheaters were built in the 1st century BC from wood and were designed by rotating and joining two theaters built back-to-back so that they formed an oval (amphitheater in fact means “double theater”).
As early as 70 BC a stone amphitheater was constructed at Pompeii at a time when the city of Rome possessed only a wooden one. Unfortunately, the amphitheater, which seated 20,000, was the site of a series of fights between hooligans of Pompeii and a neighboring town that compelled Nero to ban gladiator games in the city for ten years. An amphitheater at Arles, modeled on the Colosseum but better preserved, was the dwelling place of 2,000 people during the Middle Ages and still hosts bullfights.
The spread of Christianity in the Roman Empire caused a change in public opinion towards the gladiator games. Christians considered such games an disgrace and a waste of money which meant that there were ever fewer uses for Roman amphitheaters, and ever fewer funds to build and maintain them.
The last Roman amphitheater was built in 523 in Pavia. Eventually, many amphitheaters fell into disrepair and were gradually dismantled for building material. Of the surviving amphitheaters, many are now protected as historic monuments and have become popular tourist attractions.