Almost immediately after the Titanic sank in April 1912, there were attempts to recover the wreckage and the bodies of those who had gone down with the ship.

But the limited diving technology of the time prevented this from becoming a reality for more than seven decades.

In 1985, the wreckage was found during a joint exploration by former Navy officer and oceanographer Robert Ballard and French oceanographer Jean-Louis Michel.

But the dive initially had nothing to do with the Titanic at all – it was a secret mission to find the wrecks of two nuclear submarines, the USS Scorpion and the USS Thresher.

Of course, nobody knew that until 2008, when Ballard revealed the true nature of the mission to National Geographic.

"The Navy is finally discussing it," Ballard told National Geographic in 2008.

Originally, Ballard met with the US Navy in 1982 to secure funding for a new type of submersible technology that would allow him to find the Titanic. The Navy agreed to fund the project – but only if it could be used to find the sunken submarines.

The USS Thresher sank in April 1963, and the USS Scorpion followed two years later, in May 1965. They remain the only nuclear submarines the Navy has ever lost.

The Navy agreed that Ballard could search for the Titanic if there was any time left in the mission after finding the subs – and after confirming whether or not the Soviet Union had played any part in sinking them.

"We saw no indication of some sort of external weapon that caused the ship to go down," Ronald Thunman, the then-deputy chief of naval operations for submarine warfare, told National Geographic.

With 12 days left in the mission, Ballard was able to find the Titanic using a hunch that the ship had split in two and left a trail of debris.

"That's what saved our butts," Ballard said. "It turned out to be true."

According to Ballard, the Navy was nervous that people would catch on to why they were actually scouring the ocean floor.

"The Navy never expected me to find the Titanic, and so when that happened, they got really nervous because of the publicity," Ballard said.

"But people were so focused on the legend of the Titanic they never connected the dots."

So, 23 years later, Ballard revealed the truth about his mission. He also wrote about his experience finding the ship in his book, The Discovery of the Titanic.

"It was one thing to have won – to have found the ship," he wrote.

"It was another thing to be there. That was the spooky part."

This article was originally published by Business Insider.

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