Deep beneath pavement pounded by tourists on Paris' Left Bank lies an ancient path — a 2,000-year-old Roman road recently excavated during construction work.

Remnants of private houses rigged with baths and ingeniously heated floors were among the findings, now on view in a stunning dig. Over the next few weeks, however, archaeologists will rip up the ruins to make way for a research center.

The archeologists gradually remove every layer of ruins until they reach the geological stratum — the original ground — and eventually draw a chronological diagram.

"Excavating is destroying. We dig into historic layer after historic layer," said Didier Busson, scientific supervisor of the archaeological site.

The discovery, during construction work on the Pierre and Marie Curie University near the famed Sorbonne, offers a window onto one of the many layers of history underpinning this bustling capital.

Archaeologists said it was the first such site discovered in the city — known as Lutetia in pre-Roman and Roman Gaul — from the reign of Roman emperor Augustus (63 B.C.-14 A.D.).

Items from daily life such as flowerpots, ceramics, bronze chains and drawer handles were dug out and will soon be exhibited in museums.

"We are trying to find out about the foundation and founders of the city," Busson said, adding, "It is exceptional that a Parisian site be so well-preserved."

Archeologists are divided over the background of this neighborhood's builders. Most contend that a Gallic aristocracy, recruited by the Roman army to fight in their civil wars, probably came back from the battlefield and settled in the area.

The Romanized returnees built the city according to Roman norms, but used local materials. They were wealthy enough to own a private Roman bath — the jacuzzi of the era — found in one of the houses discovered beneath the university.

The archaeologists identified the various historical layers they uncovered according to the various types of houses they excavated. The first houses were made of clay and straw. Masonry appeared only later and so did tiled roofs — "a major chronological milestone," according to Busson.

This urban compound was built in the first decade of the 1st century, at the end of emperor Augustus's reign, away from the administrative center of the Roman city.

The neighborhood stands on the old "cardo maximus," the Roman main street, which was originally paved for the Romans to cross the nearby Seine River and is today the Rue St. Jacques in Paris' chic 5th arrondissement, or district.

Every excavated layer corresponds to a historic period.

"Paradoxically, a conservation of the sites would prevent us from learning more about ancient Paris," Busson said.

Remnants of the Convent of the Visitation, built on the site in 1632, and a 20th century sewer were found before the Roman ruins were reached, indicating that the site was abandoned between Roman times and the 17th century.

"It's like a mille-feuilles cake," said Francois Renel, Busson's assistant and an archaeologist specialized in antiquities, referring to a "thousand-leaves" pastry with many layers.

The National Institute of Preventive Archaeological Research, known by its French acronym INRAP, has been watching out for construction work in the neighborhood since they realized some 25 years ago that the Roman city of Lutetia — once thought to have only encompassed an island in the Seine — was much larger than earlier believed.

Whenever construction work in central Paris is planned, archaeologists review the building permits and ask for INRAP's opinion if the site is of interest. An excavation permit is then issued.

Busson's INRAP team started digging at the beginning of March and must be finished by June 30, when the construction work on a new research building starts again.