Italy's drought exposes ancient imperial bridge over Tiber

The ruins of the ancient Roman Neronian bridge, emerge from the river bed of the Tiber River, in Rome. Photo / AP

Italy's worst drought in 70 years has exposed the piers of an ancient bridge over the Tiber River once used by Roman emperors but which fell into disrepair by the third century.

Two piers of Nero's Bridge have been visible much of the summer near the Vittorio Emanuele bridge that traverses the river near the Vatican, a pile of moss-covered rocks where seagulls now sun themselves.

The bridge was built in the first century for Emperor Nero to reach his gardens near the Janiculum Hill near what is present-day St Peter's Square, said historian Anthony Majanlahti.

The bridge was already falling apart by the third century, and traffic was diverted to the nearby Sant'Angelo Bridge, which funnelled pilgrims past the Castel Sant'Angelo to the Vatican.

Italy's worst drought in 70 years has exposed the piers of an ancient bridge over the Tiber River once used by Roman emperors. Photo / AP

Nero's Bridge originally is believed to have had four piers, but Majanlahti says two were dismantled in the 19th century to allow for a better flow of river traffic.

"Because the water level of the river is so low now due to widespread drought across Italy, we're able to see a lot more of the piers of the bridge that we usually could," Majanlahti said.

In normal water level years, one of the bridge's piers can often be seen in the driest season, but this year two are visible.

The Italian government has declared a state of emergency in several regions because of the prolonged drought and accompanying heat wave. The drought has also exposed a World War II tank in Italy's largest river, the Po, as well as 20th century ordnance in lakes.