The H.M.S. Terror Sank in the 1840s. See What It Looks Like Now.

About 170 years ago, a pair of English naval ships and their crew vanished while exploring in the Canadian arctic.

That disappearance, the basis for the first season of the AMC series “The Terror,” captivated England. Dozens of search missions were mounted in the years that followed, but the precise whereabouts of the ships remained a mystery until only a few years ago.

Now, new footage captured this month in the ice-cold waters of Canada’s Terror Bay reveals the strikingly well-preserved wreckage of one of those ships, the H.M.S. Terror, raising the tantalizing possibility that it may hold clues to what happened to the ill-fated expedition.

Among the questions it could answer is whether some of the 129 crew members returned to the abandoned ships to try to sail one to safety, said Paul Watson, a former journalist and the author of the 2017 book “Ice Ghosts,” which documents the history of the expedition.