The narrator is actor Bill Paxton who he gets to experience what he only pretended to do as the treasure-hunting salvage diver in the blockbuster Titanic. He joins director James Cameron on the unprecedented voyage to film the sunken ocean liner more than four kilometers below the surface:

The expedition is based aboard the Russian ship Akademik Mistislav Keldysh the world's largest research vessel; and diving in its twin deep-sea submersibles [Mir I and II], they used specially designed three-dimensional cameras to tour around and inside what's left of the fabled ocean liner that sank on its maiden voyage after striking an iceberg on April 14, 1912. There were not enough lifeboats for everyone onboard and more than 1,500 people died in what is arguably the most famous shipwreck in world history.

Much of the technology was invented for Ghosts of the Abyss to give what director/producer Cameron calls a new sense of realism. "We do a couple of quick gags that say 'yes, you are watching a 3-D movie;' but after that it's really just experiential. We call it the 'reality camera system' and it creates an enhanced sense of the viewer being present in the event that's being photographed. It just kind of puts you right there and that's how I see 3-D being used most effectively," he says.

Cameron first photographed the Titanic wreck for his 1997 feature film which won the Best Picture Oscar; but he acknowledges that the fictional story set onboard the doomed liner took some dramatic license. For this documentary, he meticulously traces the true history.

"It was very strange for me going back and diving [to] the Titanic having made the movie because I almost felt like I shouldn't go back to this sacred site having had all this great success as a result of my first trip here. I almost felt like I was tempting fate. I'm not superstitious or anything like that, but you think about things like that," says the director. "Then I realized that when you become associated with or entangled with a big, tragic event like Titanic and other people who have done historical subjects, whether it's the Civil War or whatever it might be you have a responsibility to tell the truth and to continue to honor that event. I never knew any of those people. They were, for the most part, dead before I started noodling around with the Titanic subject; but I feel like you have a responsibility to tell history the way it was or to the best of your ability."

Cameron brings the human drama to life and reveals new details by superimposing filmed re-enactments precisely where the real events occurred. "We went to great pains to duplicate the tableaus, if you will the moments exactly as we think they took place. Basing it on the geometry of the wreck was interesting because a lot of the things that people had thought turned out wrong. 'He couldn't have been standing there because this would be in the way.' So there was a bit of forensic detective aspect to it that I really liked," he says.

Events of the modern world gave a different perspective to the Ghosts of the Abyss crew when they surfaced after one of their eight-hour long dives on September 11, 2001 and learned about the terror attacks that had just taken place. Cameron says the true history of Titanic has some eerie parallels. "I think the impact of the tragedy was similar in its time to what we went through. It's hard to imagine that the Titanic might have had that kind of an impact, but it did because it was such a symbol in its time of civilization the way that the World Trade Center towers were," he says. "It also helped me realize why we are attracted to Titanic because it is at a remove; it's almost a century away from us and it's almost like a story or a fable even though it really happened. It's a way for us to think about tragedy and loss and healing and how we deal with all those things in a safe way; whereas dealing with September eleventh is just too raw. We haven't processed all that stuff yet."

Ghosts of the Abyss, a new documentary by James Cameron in 3-D large screen Imax.