ROME — There were only 28 survivors, all men, and they tell the same haunting tale.

On April 18, 2015, as many as 850 migrants and refugees from Eritrea, Ethiopia, Somalia, Mali, and Senegal were taken by human traffickers on rubber dinghies at dusk to a 75-foot fishing boat with an Eritrean flag anchored a few miles off the coast of Libya. They had paid for passage to Italy—but the ship would never make it.

Instead, it toppled over during a risky rescue attempt by a merchant vessel and sank to the bottom of the sea, some 1,200 feet below the surface of the water, with most of the passengers still alive and locked into the lower hulls.

One year after the tragic wreck, the deadliest maritime accident since World War II, the Italian navy is heading out to the crash site to attempt to raise the ship, and with it the dead who are now a mass of entangled decomposed corpses.

The bodies will eventually be extracted, and volunteer forensic specialists from 24 Italian universities will start the painstaking work of identifying the dead from DNA and dental records that have been collected from family members who think their loved ones might have been on that ship. “It is about giving dignity to the dead, even if we never know their names,” said Giovanni Salvi, the prosecutor leading the case against two alleged traffickers who were among the survivors. “The world needs to be aware that this is the reality of human trafficking.”

The operation to raise the ship started last summer when the Italian navy found the wreckage after an intense search. They sent down a robot called Pegaso, which was equipped with a video camera and sonar to take a good look at the ship and try to identify any bodies that had settled onto the seabed.

What the video captured was horrific. Hundreds of bodies were intertwined, their ghost-like faces blankly staring out of the portholes and windows. Some had been partially eaten by fish, which tend to eat the ears and eyes first. Others were missing limbs. A few were caught between the seabed and the vessel. There were children, women, and young men—too many to even estimate the number.

Whenever Pegaso found a body, operators on the surface used the robot’s mechanical arm to recover it and bring it to the surface. They found 169, which means as many as 700 bodies could still be inside the ship.

The investigation of the wreckage began as part of the criminal trafficking case against the ship’s Tunisian captain, 27-year-old Mohammed Ali Malek, and his Syrian first mate, Mahmud Bikhit, 25, who both claim they were just passengers on the ship despite testimony from other survivors that pinpointed them as the men in charge. They both face multiple manslaughter charges and Ali Malek faces additional charges of causing a shipwreck.

Prosecutor Salvi asked the Italian navy if the ship could be brought up, both for investigative purposes to confirm whether the lower compartments were locked, and to “give some dignity” back to the victims.

They Italian navy is using four vessels, including a minesweeper, for the recovery. They are working in conjunction with the private company Impresub Diving and Marine, which will utilize a system of pistons and man-made strong waves to essentially “plunge” the ship off the seabed to raise it. It will be immediately contained with strong mesh netting and towed underwater to Catania, Sicily.

Once in Catania, the ship will be sprayed with liquid nitrogen as it is lifted to help preserve the bodies, which will decompose even faster once they are exposed to air. The ship will then be moved to a special hangar on the nearby NATO base, where Italy’s special rescuers from the fire brigade will start the grim work of disentangling the cadavers.

Once they are freed, the bodies will be put in a Red Cross freezer truck and then eventually thawed and examined four at a time to determine first the sex and general age. Autopsies will be performed on any intact bodies. Then DNA will be extracted from whatever bones are intact. Dental records and photos supplied by family members will also be used.

Because the identification of the victims is part of a criminal investigation, investigators will also be on site during the process, which could take years, depending on how many bodies are in the boat.

Vito Cirielli, a forensic specialist from the University of Verona, is one of 24 specialists lined up for the project. He told The Daily Beast that he anticipates the bodies in the center of the huddle of humanity will be fairly preserved. “It is possible that some can be identified by photos,” he said. “But we only have around 100 or so samples to compare with as many as 700 corpses.”

Some argue against raising a ship of nameless dead rather than leaving it on the bottom of the sea. The operation could cost as much as €500,000 a day by the time the ship is towed to Catania, which might take weeks.

When Italy’s Prime Minister Matteo Renzi announced that the boat would be recovered, he said leaving it underwater was not an option. “Europe cannot permit the bodies of our brothers to stay under 400 meters of water,” he said. “We will bring up that boat because we can no longer close our eyes to this problem.”

On April 18, the day the Italian navy set out to recover the sunken ship, four boats carrying 200 to 400 teenagers, mostly from Somalia, reportedly went down off the coast of Libya after setting sail from Egypt. If that is indeed the case, nearly 1,000 of the more than 161,000 people trying to get to Europe so far in 2016 will have already lost their lives. Most will stay buried at sea.