The Baths of Caracalla occupy a truly huge site to the south of the city.  
This particular construction was likely originally commissioned by Septimius Severus; but inaugurated in the year 216 during his son Caracalla’s reign. The opening of the baths came at a time when Caracalla had serious need of a positive public relations message given he'd recently murdered his brother, Geta, and thousands of Geta's friends in Rome. In use for roughly 300 years, the baths fell into disrepair around the time of the gothic siege of Rome in 537. Second only in size to the Baths or Diocletian which were built 100 years later, these remains are the best preserved of their kind.