More than 500 engineers from 24 countries have begun a make-or-break engineering feat to pull the crippled Costa Concordia from its side to an upright position in the waters off Tuscany, Italy.
Never before have engineers tried to right such a huge ship so close to land. The goal is to raise it from its side by 65 degrees to vertical, as a ship would normally be, for eventual towing.
The salvage operation is a highly complicated procedure and there's no predicting what will happen. The cruise liner could break apart, causing an environmental disaster or roll back onto its side. If the operation succeeds, the Concordia will be towed away and broken up for scrap.
Three hours into the operation, the salvage team reported that they managed to dislodge the vessel from the reef after 6,000 tons of force were applied.
The Costa Concordia struck a reef near Giglio Island Jan. 13, 2012, killing 32 of the 4,200 passengers and crew members. The bodies of two of the dead have never been recovered, and might lie beneath the wreckage.
The daring bid to right the ship had to be delayed early this morning because of a fierce thunderstorm. The storms prevented the positioning of the barge that stations the control room and other operative units, the project's organizers said in a statement.
The operation to bring the ship vertical is a process known as parbuckling. The first part of the operation is to free the hull from the sea floor by using 48 cables that have been looped around the hull. This is considered the most delicate and dangerous part of the operation because too much stress could cause the hull to break. Getting the ship off the seabed and onto the platforms is expected to take 10 to 12 hours.
Twenty-two hydraulic pumps will also be used to force the ship to an upright position, maneuvering the Concordia onto six underwater platforms made of steel. Then, it will eventually be towed back to shore.
Operating from a high-tech control room, engineers are watching live cameras attached to unmanned submarines, constantly monitoring the stress of the cruise liner.
Retrieving the Concordia is the most expensive maritime salvage procedure with the estimated cost of about $800 million. But engineers say now is the time for the ambitious operations because the Costa Concordia will not last another winter.
There's no guarantee this process will work and the Concordia could split apart under its own weight or fall back on its side, where it has been the past 20 months.
"It's a one-time opportunity and when we start we have to be 100 percent ready," said Nick Sloan, the engineer and salvage master who is leading the effort.
Salvage experts had originally hoped to right the 115,000-ton vessel in the spring, but heavy storms hampered work.
For the estimated 1,400 residents of Giglio Island, the partially submerged ship is a stark reminder of the harrowing night the ship ran aground and a few thousand passengers and crew members straggled ashore in the aftermath.
Since the Concordia came to rest on its side, visitors have come to gawk at the wreck, providing the tiny fishing island a year-round tourist season it never had before.
But the engineering project to right the ship has drawn some serious concern from the locals. Food and human waste are still trapped inside the partially submerged vessel and could potentially leak out during the process, causing an environmental disaster.
As a precaution, local officials told islanders last week that water tanks on the island would be topped off in case the water supply becomes contaminated.
ABC News' Clark Bentson and The Associated Press contributed to this report.