Most of us are aware that Rome possessed a harbour town at the mouth of the Tiber and that the ruins of the town are well worth a visit; but how many of us know the story of Ostia, the extraordinary interest attaching to it, the information it supplies on the economic life of Rome, and the great difficulties the Roman engineers had to face in constructing a really serviceable harbour ? Ostia lies about 20 miles from Rome, and for us, thinking in terms of motor-cars and trains, it is far from easy to imagine and to realize how long and difficult this journey must have seemed in the earliest times when the Romans first sought to establish connexion with the coast—not to speak of the dangers to which a traveller in those days must have been exposed. On arrival, we see the far-stretching ruins of the city lying before us in deep silence, for not merely its inhabitants have left Ostia but the sea and the river as well. The tawny Tiber, carrying down sand from the mountains, is the chief cause of the coastline shifting yearly no less than nine yards farther away; the river too has changed its bed and, in doing so, deprived Ostia of the last vestiges of her former greatness.