Ostia started probably as far the 5th century BC as a small military outpost to protect the mouth of the river and the coast near Rome. After its initial military role it became a major port and trading center. In its heyday it had a population of some 50000 inhabitants.
Nowadays the ancient ruins are immersed in a lush vegetation dotted with tall and elegant pine trees. After centuries of silting the shoreline moved seawards some 3 km away. The river bed instead was displaced by a flood in 1557.
The name Ostia derives from the Latin word ostium which means mouth since this town was located at the river mouth, some 30 km from Rome.
Ostia can be reached by subway train in some 40 minutes. The tour lenght is 4/5 hours including train ride from/to Rome-Ostia