Traffic lights outside the Vatican were still dead at midday
Electricity supplies are slowly being restored in Italy, after the worst power failure in its history.
Much of the capital, Rome, and the north of the country are now reconnected, and the south of Italy is also returning to normal.
Only the island of Sardinia escaped the outage, which struck at about 0330 (0130GMT) on Sunday morning.
About 110 trains were reported to have been brought to a standstill across the country - trapping more than 30,000 people.
Water supplies were also affected and hospitals reported a spate of accidents involving elderly people.
Officials have warned that scheduled cuts may still be necessary.
It is the latest in a series of major blackouts to affect national power grids - north-east United States and Canada were hit last month, and Denmark and southern Sweden on Tuesday.
A power cut left London's underground transport in chaos last month.
A row has broken out over the origin of the fault - the Italian national grid authority says malfunctioning supply lines from France caused the outage, but France says it originated in Switzerland.
A Swiss power company said the problem began when a tree touched a transmission line near the town of Brunnen.
Neighbouring areas of Switzerland and Austria were also hit.
France and Italy have a long-standing electricity exchange scheme to help deal with peaks in demand on both sides.
White night in the dark
In Rome, the power cut struck as thousands of people celebrated the city's first "White Night" - an extravaganza of street events.
The failure halted the free underground service provided by the city, and left passengers stranded in underground trains.
Heavy rain had already stopped a number of attractions.
The lights also failed inside the Vatican, although emergency generators are now operating there as they are at Rome's hospitals and key government ministries.
Emergency services coped fairly well with the situation, says the BBC's David Willey in Rome, although several accidents have been reported as a result of the failure of traffic signals.
Hospitals have also reported a spate of home accidents involving elderly people who broke limbs through falls in the dark.
The water supply was also affected.
A spokesman for the Italian national grid said it had lost control of power flowing through the grid for four vital seconds - sparking the successive shutdowns.
Two major supply lines from France have been blamed.
But French officials said the fault came from Switzerland - probably due to foul weather.
The problem was "eliminated well in France but wasn't correctly eliminated in Italy," French national grid director Andre Merlin told France-Info radio.
Italy suffered partial power cuts in June, when the system was strained by heavy use of air conditioners and other electric items.
The national grid operator has repeatedly said power demand is growing faster than supply and that imported electricity would not make up for insufficient production in the long term.
Following Sunday's major failure, ministers have authorised the construction of 20 new power stations, Italian news agency Ansa said.