There are two Ostias: one a rather over-visited seaside resort, Lido di Ostia; the other, one of the finest ancient Roman sites – the excavations of OSTIA ANTICA – which are on a par with anything you’ll see in Rome itself (or indeed elsewhere in Italy) and easily merit the half-day journey out.
The site of Ostia Antica marked the coastline in classical times, and the town which grew up here was the port of ancient Rome, a thriving place whose commercial activities were vital to the city further upstream. The excavations are relatively free of tourists, and it’s much easier to reconstruct a Roman town from these than from any amount of pottering around the Roman Forum. It’s also very spread out, so be prepared for a fair amount of walking.
The main street, the Decumanus Maximus, leads west from the entrance, past the Baths of Neptune on the right (where there’s an interesting mosaic) to the town’s commercial centre, otherwise known as the Piazzale delle Corporazioni, for the remains of shops and trading offices that still fringe the central square. These represented commercial enterprises from all over the ancient world, and the mosaics just in front denote their trade – grain merchants, ship-fitters, rope makers and the like. Flanking one side of the square, the theatre has been much restored but is nonetheless impressive, enlarged by Septimius Severus in the second century AD to hold up to four thousand people. On the left of the square, the House of Apulius preserves mosaic floors and, beyond, a dark-aisled mithraeum has more mosaics illustrating the cult’s practices. Behind here – past the substantial remains of the horrea or warehouses that once stood all over the city – the Casa di Diana is probably the best-preserved private house in Ostia, with a dark, mysterious set of rooms around a central courtyard, again with a mithraeum at the back. You can climb up to its roof for a fine view of the rest of the site, afterwards crossing the road to the Thermopolium – an ancient Roman café, complete with seats outside, a high counter, display shelves and even wall paintings of parts of the menu. North of the Casa di Diana, the Museo Ostiense holds a variety of articles from the site, including a statue of Mithras killing a bull, wall paintings depicting domestic life in Ostia, and some fine sarcophagi and statuary from the imperial period. Left from here, the Forum centres on the Capitol building, reached by a wide flight of steps, and is fringed by the remains of baths and a basilica. Further on down the main street, more horrea, superbly preserved and complete with pediment and names inscribed on the marble, merit a detour off to the right; although you can’t enter, you can peer into the courtyard. Beyond, the House of Cupid and Psyche has a courtyard you can walk into, its rooms clearly discernible on one side, a colourful marbled floor on the other.