Italian authorities say that tourists are loving their visit to Rome so much, they're trying to take a bit of the city back home with them.
According to the Telegraph, security at the capital's Fiumicino and Ciampino airports say their staffs have noticed an increase in cobblestones and other artifacts showing up in fliers' luggage during X-ray screenings.
"The phenomenon is definitely on the increase," said Antonio del Grego, head of Fiumicino's frontier police. "The airport police and security are on the alert."
Though some media reports said the pieces looked more like the modern-day cobblestones now mostly made in China, del Grego said that was not the case.
"Most of the cobblestones we found are the handmade ones from the 1900s," del Grego told ABC News today. "They are not the newer ones."
In addition to the blocks, tourists have also reportedly tried to transport volcanic rock, ancient Roman mosaics and milestone.
"Some of the bits of archaeological pieces could be from the Colosseum, we think, but it is hard to identify from where they were taken from," del Grego said.
The frontier police head said that an expert had confirmed that a mosaic uncovered in a person's baggage had come from an archaeological site at Ostia Antica, an ancient Roman port.
In the last six months, 10 people have been denounced for theft. Del Grego said that none of the people stopped had been American.
"Many of them are people from northern Europe of a certain age," he said. "It is hard because we have to prove that these items are stolen and as the value of the stolen good is of little value and we often don't know where it comes from, this is difficult."
Del Grego told the Telegraph that those found with stones or other artifacts were not arrested. They are cautioned and the artifacts are returned to the city.
"More than the judicial proceeding, what we hope will put people off is the shame they will feel when they are discovered," he said. "Then along with the shame, some even miss their flights."
ABC News' Phoebe Natanson contributed to this story.