For 160 years, searchers have tried to solve one of the biggest enigmas in maritime history: What became of the two ships that explorer Sir John Franklin sailed into the icy seas of northern Canada, hoping to discover a passage from the Atlantic Ocean through to the Pacific?

A team of underwater archaeologists discovered the flagship, HMS Erebus, two years ago.

Now, a crew of scientists has located the second ship, HMS Terror.

Both have tantalised historians and adventurers for centuries.

The crew that discovered the Terror. ( Supplied: Adrian Schimnowski )

The wreck was found in the late northern summer, as ice was closing in, and its identity as the Terror officially confirmed by Parks Canada only recently.

Scientists involved say the winter is going to feel especially long this year — because they are itching to go back when the ice melts again, and seriously explore the two wrecks.

The Arctic has no substantial land mass, just islands and ice.

In summer, it is navigable for a couple of months, while the winter brings endless freezing whiteness — a survival test for anyone.

The Franklin expedition to find the fabled Northwest Passage began in May 1845 when 129 men sailed from England.

The quest — equivalent to a moon-landing for the time — ended years later, when every last man died.

The fate of the ships inspired artwork, music and literature, including this sketch by Owen Stanley. ( Supplied: Library and Archives Canada/1960-109-36. )

A number of rescue missions were dispatched from Britain to find the men — all failed.

Intensive searches ever since gradually discovered the crew's frozen bodies and remnants of the disaster.

A note found hidden in rocks recorded that Sir John Franklin died on June 11, 1847.

Evidence has revealed there was hunger, starvation, severe frostbite and even cannibalism, as fewer and fewer men pushed southward to reach a trading post before death found them.

At the end, there was only horror.

Many of the ship's features are still in their original location, such as the ship's wheel. ( Supplied: Parks Canada )

The latest discovery will rewrite the history books on the circumstances under which the Terror was abandoned.

"The ship had been intentionally left," said Adrian Schimnowski, operations director of the charitable Arctic Research Foundation expedition, which made the discovery.

"The crew was in much more control of the ship than originally thought.

"They may have re-manned it more than once, in an effort to find their way home."

The two ships are in very different states of repair.

Erebus sits in 11 metres of water, its stern badly damaged by churning sea ice. Its upper deck heaves with the motion of waves and currents.

Fifty kilometres away, the Terror is in almost pristine condition, sitting level on the ocean floor, 24 metres down.

Its six-metre bowsprit is in place, and its windows intact.

A robotic probe was manoeuvred into the mess hall, where it spotted tables, a desk, plates, wine bottles and empty shelves — except for one tin can.

Sir John Franklin's illustrious career in colonial Australia

Sir John Franklin, born in England in 1786, honed his sailing skills exploring Australia.

John Franklin was a midshipman for Captain Matthew Flinders when he was charting the Australian coast. ( Supplied: Dibner Library Portrait Collection )

After earlier voyages and battles, he was chosen as midshipman for Captain Matthew Flinders when he charted the Australian coast, sailing right around the continent in 1802-03.

After exploring the icy coast of Antarctica, Sir John, with his wife Lady Jane, left the seas for a commission as Lieutenant-Governor of Van Diemen's Land in 1837.

His next seven years were rocky and ended badly, as his progressive ideas ran foul of London's grim, unmoving hand.

"He had expected to end convict transportation, and introduce local government — instead the Colonial Office sent more convicts," historian Andrew Lambert wrote.

Sir John began the process that saw the island officially renamed Tasmania, but he never saw it completed, as London removed him from office.

His otherwise illustrious career was blighted — but it was in Hobart that fate beckoned.

There, according to the chief executive of the Royal Canadian Geographical Society, John Geiger, Sir John probably first beheld the majestic ships that would eventually carry him to his end.

How Inuit lore helped uncover the Terror's resting place

Mr Geiger has been intimately involved in recent searches for the legendary lost ships.

Erebus was eventually located, not just through science and good luck.

A captain's cabin window at the ship's stern is still in place. ( Supplied: Parks Canada )

The expedition also followed Inuit lore, he said, which records accurate information in stories handed down from generation to generation.

"The knowledge in that tradition is a very powerful tool. It's been overlooked and discarded by many people," he said.

It was listening to Inuit information that finally broke the spell of finding the Terror.

About five weeks ago, time was running out for the crew aboard the search ship. It felt like yet another frustrating failure.

Snow flurries were in the air and the days were getting colder. It was at that point Inuit crew member and Canadian ranger Sammy Kogvik spoke with Mr Schimnowski.

Mr Kogvik recounted hesitantly that six or seven years earlier, he and a friend had been hunting on the ice on Terror Bay — so-named in memory of the fated ship.

Map Sir John Franklin's crew were trying to find a navigable route between the Atlantic and Pacific oceans.

They had spotted a timber, perhaps a mast, inexplicably jutting from the ice.

Unanswered questions beneath Arctic waters

But for Mr Kogvik, the story was associated with sad memories of a lost friend and a bad omen, and he had kept it to himself.

"I think he was waiting for the right time, maybe to recover from the passing of his great friend, but also to tell it to the right group of people whom he could trust, and know that there would be respect," Mr Schimnowski said.

The ship's crew diverted to Terror Bay and to the location Mr Kogvik identified — within hours, on the morning of September 3, the long-lost ship was found.

Mr Geiger said a new chapter in the Franklin story was just beginning.

"Everyone who has an interest [in] Franklin is eagerly awaiting gathering materials from the vessels," he said.

"The journals of the expedition have never been found, perhaps the ship's logs will be there."

Researchers hope some of the crew's personal effects may be intact, along with books and diaries.

Tantalisingly, it is known that primitive photographic equipment was on board, teasing out the possibility of finding glass plate images.

Ironically, the end of the search for Franklin's ships has provoked dozens of questions.

Answers to many of them are lying beneath the Arctic waters, just waiting for next summer to yield them.