Baiae, the underwater city

   Located near Maples on the Gulf of Pozzuoli, Baiae was ancient Rome's counterpart of modern-day Monte Carlo. Magnificent pavilions were built out on the sea atop raised foundations. Expansive villas dot-ted the coastline, and marble statues of deities graced the cobble-stone streets. Named by the Greeks after Baios, helmsman of the legendary Ulysses, Baiae was also famous for its sulphur springs, said to relieve arthritis and rheumatism. The city had also earned a reputation for satisfying the vacationing Roman's every appetite.

   But this "favored city of the emperors," as one historian called Baiae, largely vanished from hu­man view, the victim of a phenomenon that has plagued the coastal cities of Italy for centuries. Some legends liken Baiae's fate to that of the biblical Sodom and Gomorrah, destroyed by divine powers as punishment for their inhabitants' evil ways. But its demise stemmed from a purely geological process called bradyseism, a combination of volcanic activity and subterranean erosion. The seafloor along Italy's west coast is part of the so-called Phlegraean Fields, a honeycomb of volcanic chambers that release hot gases and mud, causing the coastline above to shift.

   Usually, the seismic action works slowly, moving land almost imperceptibly up or down over long intervals of time. Such changes doubtless frightened the Romans and led to Baiae's gradual evacuation. Then, in 1538, the volcano Monte Nuovo erupted, and overnight, the remains of the Ro­man resort—and miles of shore-line—slipped into the sea, where it endures today beneath ten to fifteen feet of water.

   But nothing is forever along Italy's volcanically active coast. In 1983, a series of earthquakes and volcanic action lifted the seafloor at nearby Pozzuoli, across the bay, raising the ruins of an ancient Ro­man market that had been inundated only eight years before. Perhaps the forces that submerged it will one day restore ancient Ba­iae to the light.