Fazio said there are only eight people left trained to hammer the stones into place, a task that requires considerable skill and, he says, “no little muscle,” while supplies of the cobblestones themselves have been stretched in recent years as the last workshops producing them closed down.

The stones were produced from deposits of volcanic rock that once spewed from the hills around Rome.

Though sampietrini that are removed are recycled, the city resorted to importing machine-made cobblestones from China amid efforts to spruce up Rome for jubilee celebrations in 2000. Fazio said that the experiment was dropped after engineers complained about the quality of those stones. —Aidan Lewis —Rome Ending Cobblestone Era (AP|MyWay)