Engineering teams have begun lifting the wrecked Costa Concordia liner upright, the start of one of the most complex and costly maritime salvage operations ever attempted.
After a three-hour delay caused by an overnight storm which interrupted final preparations, salvage crews started the all-day operation at around 9:00am local time (0700 GMT) on Monday.
A complex system of pulleys and counterweights began pulling upright the cruise ship from its side on a Tuscan reef where it capsized in 2012.
There, engineers using remote controls will guide a synchronised leverage system of pulleys, counterweights and huge chains looped under the Concordia to delicately move the ship free from its rocky seabed perch just outside the island's harbour.
The goal is to raise it 65 degrees to vertical for eventual towing.
Righting the ship is expected to take up to 12 hours.
"The intial weight supported by the pulley system is 2,000 tonnes, that will allow us to check everything, and alternate the pulls from different positions to check the behaviour of the hydraulic system, that it's all working fine, and for the moment we'll move forward 200 tonnes at a time," Engineer Sergio Girotto explained.
The intial weight supported by the pulley system is 2,000 tonnes, that will allow us to check everything, and alternate the pulls from different positions...
He said it would take another couple of hours before any movement will be visible from shore.
The operation, known in nautical parlance as parbuckling, is a proven method to raise capsized vessels, but the Concordia is thought to be the largest cruise ship to ever require it.
The Concordia crashed into a reef on a winter's night January 13, 2012.
Thirty-two people were killed after the captain steered the luxury liner too close to the rocky coastline of Giglio, part of a chain of islands in pristine waters off the coast of Tuscany.
The reef sliced a 70-metre long cut into what is now the exposed side off the hull, letting seawater rush in.
The resulting tilt was so drastic that many lifeboats could not be launched.
Dozens of the 4,200 passengers and crew were saved by helicopters or jumped into the sea and swam to shore.
Bodies of many of the dead were retrieved inside the ship, although two bodies were never found and might lie beneath the wreckage.
'No plan B'
Never before have engineers tried to right such a huge ship so close to land. If the operation succeeds, the Concordia will be towed away and broken up for scrap.
Salvage experts had originally hoped to right the 115,000 tonne vessel last spring, but heavy storms hampered work.
Crews have raced to get the Concordia upright before another winter season batters the ship against its rocky perch - damage that would increase the chance that it could not be towed away in one piece.
Al Jazeera's Charlie Angela, reporting from Giglio, said there was no "Plan B" if the rotation failed since there would be no other way to try again.
"The salvage experts say it has to work, they have only one chance of doing this and once they start this operation, they can’t stop it."
Nick Sloane, the South African who is senior salvage master, said he was confident the ship would withstand the stress of the rotation.
Authorities have asked for patience from the island's 1,400 residents during Monday's operation.