The Wilhelm Gustloff was one of the two ships on Operation Hannibal. Operation Hannibal was a mass evacuation of people and soldiers from the East Prussia area, because the Russians were pushing in. Poland was invaded from both sides, and they were trapped in the middle The ship after leaving held nearly ten thousand people, soldiers and civilians, on board. The trip had four ships, the Wilhelm Gustloff, another passenger ship called the Hansa, and two torpedo boats. The ship was originally made for the "Strength Through Joy" program. It was a cruise ship, and was made to hold just under two thousand people.

The ship left for Operation Hannibal on January 30. The Captain Friedrich Petersen ignored the recommendation that the ship should take a route closer to the coastline. He also ignored the recommendation that he should increase the speed of the boat from 12 knots to 15 knots, in order to decrease the chances of being attacked, as the Russian submarines wouldn't be able to stay at that speed. Instead, he kept the speed at 12 knots, because he was worried that the engine could fail after not being used for years. Although the trip was originally made to have four ships, one of the torpedo ships and the Hansa had to return because of mechanical issues.

The Captain was told about a minesweeping ship that was going to cross their path, and so he turned on the navigation lights, so they wouldn't collide. However, because of this, the ship was spotted by a submarine. The ship was then hit with three torpedoes from the Russian Submarine. Lifeboats and rafts only accounted for five thousand people, much less than the estimated ten thousand. Even then, many of these boats were frozen onto the ship, and were not able to be used. Only 1,239 people could be registered as survivors, giving it the highest death count, multiple times higher than even the Titanic.