Between the Colosseum and the Palatine Hill sits one of the best-preserved monuments of ancient Rome, the Arch of Constantine is the largest of three that still stand today.

Built by Constantine to celebrate his victory over his rival Maxentius in 312, the triple arch is on the road taken by the triumphal processions. The arches are built using recycled remains of older Roman monuments, and using various construction techniques, which some theories argue might be indicative of several periods of construction.

This massive fortress is known by several names: Angevin Castle, after its founder; New Castle, or Castelnuovo in Italian, to distinguish it from another castle nearby, which is about 300 years older; and locally as the Maschio Angioino, also a reference to the founder Charles I of Naples.

A descendent of a medieval French dynasty, he – like the castle – is also known by another name: Charles of Anjou. The castle is a fascinating trapezoidal building with five round towers.