A builder's mistake has cut off the water supply to one of Rome's most famous fountains - the Trevi.
Water company Acea said the wall of an ancient Roman aqueduct which supplies the fountain was damaged by builders constructing an underground garage.
Water from a second aqueduct has been redirected to the Trevi to avoid the spectacle of it running dry.
The Trevi, a baroque landmark dating from the 18th Century, was popularised by films such as La Dolce Vita.
"The problem is that they damaged the aqueduct. It's more than 2,000 years old and has archaeological value as well," Acea's Giorgio Signore told the BBC News website.
The builder of a new car park in northern Rome partially walled up the Aqua Virgo conduit after damaging its structure, plugging the flow of the water.
"The Aqua Virgo aqueduct was one of two Roman water channels built underground. It was one of the few to escape being destroyed by the barbarians and to survive intact," Mr Signore said.
"Unfortunately, it has been destroyed by their descendants," he added.
The Aqua Virgo conduit was originally constructed by Marcus Agrippa during the reign of the Emperor Augustus.
Both surviving Roman aqueducts supply non-potable water that flows through many of the fountains which grace the city's squares, as well as watering its public parks and gardens.
Ancient Romans built a series of aqueducts and conduits to supply the city with water, some of which were subsequently restored by various popes during the Middle Ages.
During the Aqua Virgo's latest repair works, estimated to take at least two months, water will be redirected from the other surviving underground aqueduct into the Trevi Fountain.
But in the short term, the water currently gushing through the fountain will have to be recycled to avoid turning it off.
"We can repair it but we can't really reconstruct it the way it was built," Mr Signore said.