A former BBC NI journalist who made the journey to the bottom of the Atlantic ocean to visit the wreck of the Titanic has spoken of the dangers faced by those who undertake the challenge.
Mike McKimm joined an expedition to the wreck site in 2005, traveling 3,795 metres to the ocean floor in a Russian MIR submersible.
At the site, around 370 miles off the coast of Newfoundland, Canada, the crew in the tiny vehicle left two memorial plaques on behalf of Belfast City Council and Harland and Wolff, the company which built the ill-fated liner ahead of its maiden journey in 1912.
Mr McKimm spoke to BBC NI on Tuesday of his journey, as searches continue in the North Atlantic for the missing Titan tourist submarine, which contained five people who were visiting the wreckage.
Those on board lost contact with the small OceanGate tourist submarine about an hour and 45 minutes into its dive towards the Titanic wreck on Sunday.
The US Coast Guard estimated the sub had roughly four days of oxygen left, as of 5pm on Monday.
Mr McKimm told the broadcaster that the submersible he travelled in, measuring just 6ft in diameter, was like a "tiny steel ball", adding he was "very, very nervous" during the descent.
Ahead of the journey, Mr McKimm signed a document stating he took responsibility and accepted the risks involved.
His expedition was accompanied by another crew in a separate submersible, which meant an alarm could be raised if either sub faced difficulties.
"You're very conscious all the time of what's happening around you, listening to noises, there's condensation forming inside of the shell which is sending off alarms," he told BBC NI.
"It was my first dive so I was very, very nervous. I can only begin to imagine what these people are going through."
Describing the moment when his sub lost power, he said: "Nobody knew what was going on.
"In those 20 minutes you've a lot to think about and you realise just how dangerous it all is, diving at that depth is a very dangerous pastime, the risks are very, very high."
The former journalist, who was documenting the wreckage during his descent, described the darkness of the Atlantic ocean as "blacker than you could ever imagine" with temperatures dropping to 2C.
"It is very claustrophobic," he added. "For people just sitting as tourists, looking around, there's a lot that can go through your mind."
He added that the task of rescuing those lost in the Atlantic is "mammoth, but not impossible".
