The United States repatriates a fresco depicting the Greek hero Hercules and 59 other artifacts initially from Pompeii, a city destroyed in 79 A.D. after the eruption of Mount Vesuvius.

Last summer, U.S. authorities announced that the fresco and dozens of other trafficked objects, which ended up in private collections in the United States, would return to Italy.

Among the precious pieces Italian and U.S. officials displayed to journalists in Rome is a B.C. kylix, or shallow two-handled drinking vessel, some 2,600 years old. Also returned is a sculpted marble head from the second century B.C., depicting the goddess Athena.

Italy said the returned works are worth more than $20 million.

The fresco, done in the classic style of Pompeiian art, depicts Hercules as a child strangling a snake.

The returned pieces had been sold by art dealers, ended up in private U.S. collections, and lacked documentation to prove they could be legally brought abroad from Italy.

Under a 1909 Italian law, archaeological objects excavated in Italy cannot leave the country without permission unless taken abroad before the law was made.

Among those at Monday's presentation was Manhattan Assistant District Attorney Matthew Bogdanos, chief of that office's unit combating illicit trafficking in antiquities. On this investigation, his office worked jointly with a specialized art squad branch of Italy's paramilitary Carabinieri.

"For Italian antiquities alone, we have executed 75 raids and recovered more than 500 priceless treasures valued at more than $55 million,'' Bogdanos said.

Italy has been a pioneer in retrieving illegally exported antiquities from museums and private collections abroad.

The country has been so prosperous in recovering such ancient artworks and artifacts that it created a museum for them. The Museum of Rescued Art was inaugurated in June in a hollow structure that is part of Rome’s ancient Baths of Diocletian.

Italian cultural authorities are deciding whether to assign the latest returned pieces to museums near where they were believed to have been excavated. Culture Minister Gennaro Sangiuliano told reporters that another possibility is having a special exhibition of the returned pieces.

It's not only Italy that loses pieces of its history when artifacts are discovered in clandestine excavations and smuggled off to art dealers for profitable sales. Academic experts, deprived of valuable information about the context of the area where the objects were found initially, lose out on knowledge about past civilizations.