Remains of a Roman neighborhood have been discovered in Sainte-Colombe, near Vienne, eastern France. JEAN-PHILIPPE KSIAZEK/AFP/Getty Images

Hundreds of years ago, in the late 1st century A.D., this neighborhood near the Rhône River, in what’s now southwestern France, was a place for wealthy Romans to build sumptuous houses. For 300 years or so, families made their homes here, until one day a fire forced them out. The neighborhood was abandoned, buried under ash, and forgotten.

Now, as a developer prepares to build new houses here, not far from Lyon, archaeologists have rediscovered this hidden Roman neighborhood. The site is unusually well preserved because of the ash that fell over the buildings. Benjamin Clément, who’s leading the excavation of the site, is calling it a “Little Pompeii.”

The site is large, about 75,000 square feet in area; among the most incredible finds are a residence with an intact mosaic of maenads and satyrs, another with a mosaic of a half-naked muse being kidnapped by Pan, and a public building featuring a statue of Hercules. These were the buildings used by wealthy people: the team has found evidence of sumptuous gardens and interior water supply systems. Overall, says Clément, it is the “most exceptional excavation of a Roman site in 40 or 50 years.”