In 1845, Captain Franklin, an officer in the British Royal Navy, took two ships and 129 men towards the Northwest Territories in an attempt to map the Northwest Passage, a route that would allow sailors to travel from the Atlantic to the Pacific via the icy Arctic circle.
Stocked with provisions that could last for seven years, and outfitted with the latest technology and experienced men, the two ships - HMS Erebus and HMS Terror - were some of the biggest, strongest, vessels ever to make the journey.
But the men vanished into the frozen Arctic, leaving a few clues but no explanation as to what went wrong.
The first search party set off in 1848 and searches involving teams from Canada, the UK, and the US have continued ever since. Last week, representatives from Parks Canada announced the results from their search this summer, which proved unsuccessful.