Baia: Exploring the real-life Atlantis, once ancient Rome's Sin City

It was once the vacation home of Julius Caesar. And it may have been within eyeshot of the spot where the plot to murder him was conceived. Now, the once-opulent Roman city of Baia sits under the Bay of Naples, a victim of volcanic activity like its nearby neighbor Pompeii.

For 60 Minutes Plus this week, correspondent Seth Doane explored the ruins of the sunken city, reporting on the luxury and debauchery that defined Baia.

Written accounts from the time of the city called it a "resort of vice" full of wild parties. One philosopher wrote that Baia was "a place to be avoided..." and that he saw "persons wandering drunk along the beach," noting, "luxury has claimed it for her own exclusive resort."

It was also a seat of power. The former head of archaeology for Italy's Ministry of Cultural Heritage, Stefano De Caro, noted that while Pompeii is more famous today because of how it was preserved, senators were not vacationing there.

"But senators were here in Baia," De Caro told Doane, "emperors too."

Doane's report utilized 3D models depicting how the city once looked from archeologist Barbara Davidde, who leads Italy's Department of Underwater Cultural Heritage. She told Doane about the challenges that come with preserving and restoring an underwater archaeological site.

"Restoring underwater is a challenge, of course, but after all of these years we are-- improve and improve the tools and the materials," Davidde said.

Davidde led Doane through the underwater remnants of the city, showing where toppled columns once stood and steps that likely led from a pool. Even after centuries underwater, some of the city's mosaics still retain their color. In its prime, the submerged portion of the city had more than 400 acres of lavish villas and spas.

See more of the story on 60 Minutes Plus, streaming now on Paramount+.