Rare video footage showing the Titanic ocean liner on the floor of the Atlantic is being released on Wednesday, decades after the discovery of the wreckage and more than a century after the ship hit an iceberg and sunk.

The footage from Woods Hole Oceanographic Institution (WHOI) was shot about 2 miles (3 kilometers) below the ocean’s surface, just months after explorers found the wreckage in 1985. Most of it has not been previously released to the public.

Since the discovery, several documentaries about the Titanic have showed footage of the wreckage scene. Some brief clips of the original dives have been aired, but Wednesday will see the release of a longer 80-minute video of uncut footage on YouTube.

The release of the footage “marks the first time humans set eyes on the ill-fated ship since 1912 and includes many other iconic scenes,” the WHOI said.

The Titanic, thought to be nearly impregnable when it was built, was the largest ocean liner in service at the time. It struck an iceberg on April 14, 1912, in the Atlantic as it made its maiden voyage from Southampton, England, to New York. More than 1,500 people died in the sinking, shocking the world and prompting outrage over a lack of lifeboats on board.

A team from WHOI and the French National Institute of Oceanography found the sunken ship broken in two pieces southeast of Canada’s Newfoundland on Sept. 1, 1985.

During 11 dives in July 1986, footage was shot by cameras on a human-occupied submersible and a small remotely operated vessel that maneuvered through tight spaces.

The unveiling of the footage has been timed with the re-release of director James Cameron’s 1997 film “Titanic” on its 25th anniversary. The movie won 11 Academy Awards, including for best picture.

“The human stories embodied in the great ship continue to resonate,” Cameron said in a statement. “By releasing this footage, WHOI is helping tell an important part of a story that spans generations and circles the globe.”

By Brendan O’Brien