Engineers are preparing to raise the Costa Concordia cruise ship a few days from now, it has been announced.
The 114,500-ton luxury liner capsized off the island of Giglio, with 4,229 passengers and crew on board, in January 2012.
It has been lying on its side ever since, but on Monday a salvage team will begin the first of five phases to "parbuckle" (upright) the vessel so it can be towed to a scrap yard.
Franco Gabrielli is heading the operation, details of which have recently emerged . He said: "If weather conditions allow, the operation will start at 6.00 am (4am UK time) on September 16.
"This is an operation that has never been attempted before."
The feat will involve 500 engineers and divers from 21 countries who have worked around the clock to ensure the operation will be a success.
Using giant cement sacks and a custom-made metal platform, the salvage operation has so far secured the rusting hulk, which was threatening to slip off an underwater rock shelf into deeper waters.
The plan is to drag it up using ropes and pulleys - a complex and delicate operation since the hull of the ship is badly damaged 20 months after the crash.
Italy's civil protection agency said the official go-ahead would be given only on Sunday afternoon.
The operation is now expected to be completed in a single day and officials have said they will block all maritime traffic in the area until it is over.
"The size of the ship and its location make this the most challenging operation I've ever been involved in," said Nick Sloane, the chief salvage operator.
He fears there is a chance the hull could buckle, but Mr Gabrielli ruled out the possibility of the hull splitting in two.
The salvage operation is the biggest ever attempted for a passenger ship and has been delayed repeatedly, mainly because of the difficulty of drilling holes in the granite seabed to install the platform intended to keep the ship upright before it is towed away.
Retrieval of fuel from the ship's 15 tanks and collection of 240 cubic metres of waste water and sewage to prevent pollution, was completed earlier this year.
Environmentalists have warned of the potential danger of toxic chemicals from the ship pouring into the sea as it is rolled over.
Mr Gabrielli admitted there would be some spillage as it is being raised but said preparations had been made to contain it using floating booms and clean it up.
The project is being financed by insurance for ship owner Costa Crociere, Europe's biggest cruise operator and a part of US giant Carnival.
Insurance companies have said the total cost of the salvage could be $1.1bn (£695,446) but officials on Thursday said it was €600m (£504m) "and rising".
The ship struck a reef, took on water and listed badly before capsizing off Giglio's port, killing 30 people and leaving two missing, presumed dead.
The manslaughter trial of the Concordia's captain, Francesco Schettino, resumes on September 23. Prosecutors alleged he steered the boat too close to shore, though he claims the reef did not appear on his navigational charts.