--- Ostia Antica (Ancient Ostia) is a large archaeological site, close to the modern town of Ostia, that is the location of the harbour city of ancient Rome, 25 kilometres southwest of Rome.
--- The name Ostia (the plural of ostium) derives from Latin os 'mouth'. At the mouth of the Tiber River, Ostia was Rome's seaport, but due to silting the site now lies 3 kilometres from the sea.
--- The site is noted for the excellent preservation of its ancient buildings, magnificent frescoes and impressive mosaics.