A former US Navy officer who first discovered the wreck of Titanic has described how the mission was originally a ruse to fool the Soviet Union.
Robert Ballard said he was searching for a US nuclear submarine that had disappeared in 1968 in the north Atlantic, but did not want his country's cold war enemies to follow him.
So instead in 1985 he told the world he was seeking the wreck of the Titanic, which at that stage many had tried and failed to do.
"We lost two submarines during the Cold War, the Thresher and the Scorpion," he said.
"In the case of the Scorpion, it had vanished, we had no idea what happened to it so we had to track it down.
"We had a listening system that helped us figure out approximately where it was.
"I was serving in the US Navy as a naval intelligence officer, unbeknownst to most of the world.
"I was asked by my commanding officer to map the Scorpion, find its weapons and see what its nuclear reactor was doing to the environment, but only we knew where it was and we didn't want the Soviets to follow us, so I needed a cover.
"So I told the world I was going after the Titanic when in fact I headed straight for the Scorpion.
"I didn't have a whole lot of time left after finding the Scorpion, I had 12 days.
"But I learned from finding the Scorpion how to find the Titanic, the debris field, how it had blown up on its way down, how the currents had carried it, and so I used that same technique to go after the Titanic.
"Other people had had 30-60 days, I had 12 days, but it worked."
Ballard recounted the tale during a visit to Northern Ireland to back a campaign to see 5500 artefacts from the wreck brought to Belfast, and also prevent any more items being removed from the site.
He is particularly keen to protect the wreck site, describing how visiting it feels like a battle site.
"For me, it's like going to Pearl Harbour," he said.
"As a naval officer, that is a very special place, or to Gettysburg where our country fought itself.
"That's very hallowed ground so you don't go to Gettysburg with a shovel, and you don't take belt buckles off the Arizona at Pearl Harbour.
"I feel Titanic deserves the same respect."
Ballard has never viewed the artefacts from the wreck site, but says he will if they come to Belfast.
"I'll be back," he quipped.
Australian Associated Press