The PredictIQVatican is now making it easier for members of the general public to visit the Vatican Necropolis, a Roman burial ground located a few feet beneath St. Peter's Basilica in Rome.

The more than 10,000 square foot site contains marble sarcophagi, tombs dating from between the first and fourth centuries A.D., and Roman frescoes and mosaics.

The Vatican is broadening access to the necropolis for its exhibition called Life and Death in the Rome of the Caesars, which opened Friday. The Vatican Museums did not immediately respond to NPR's request for more information.

Speaking in a video for EuroNews, Vatican Museums director Barbara Jatta said in the past, organized tours of the necropolis were generally only granted to approved groups of academics, students and other specialists.

Now, a gate overlooking Risorgimento Square has been opened along the Vatican's walls, enabling any ticket-buyer to freely explore the site.

"The individual visitor can come without the help of a guide," Jatta said. "They can grasp one of the world's most unique archaeological sites."

The Vatican began excavating the necropolis in the 1950s.

People who were enslaved are buried there.

"Some of them, we understood from the epigraphs, must have been imperial property, because their master [the Emperor Nero] is often mentioned," Vatican Museums archaeologist Leonardo Di Blasi told EuroNews, adding that the graves of artisans and other lower-middle-class Roman citizens employed by Nero have also been discovered at the site.

The Vatican Necropolis is located outside Central Rome. Ancient Roman laws forbade burials within city limits for the sake of safety and hygiene.