Cameron with wife Suzy Amis last April at the Beijing International Film Festival. (Reuters)

Calcutta, May 24: The world may know him as the maker of Titanic and Avatar, the two highest-grossing films of all time, but James Cameron tells The Telegraph that he is an explorer first.

Two months ago, on March 26, the 57-year-old descended 6.8 miles to the spot known as the Challenger Deep in the Pacific Ocean’s Mariana Trench, an area deeper than Mt Everest is tall.

The trip was part of Deepsea Challenge, a joint scientific expedition by Cameron and National Geographic. Cameron is the only individual to have completed the dive in a solo vehicle and the first person since 1960 to have reached the bottom of the world in a submersible.

Cameron answers questions from this newspaper over email:

Since when have you been interested in the deep sea?

This is a lifelong dream. Most people know me as a filmmaker but my passion is the ocean and its exploration.

What drove you to achieve this feat?

We had been preparing for this for the last seven years, and the dive was a culmination of a seven-year project. The point is that a billion people on the planet can’t go to all these places; but if one person goes and they bring back the story, then everybody goes in spirit.

How did you prepare?

We were going to be fighting against the absolute limits of material science. This seemed like a very daunting thing and we didn’t even know if we could do it. The design of the sub called for things that didn’t exist.

It’s holding back the force of the ocean — millions and millions of pounds when you distribute it over the whole surface of the sphere. And if it buckles at pressure, it implodes. Everything on the sub has to be adapted or invented to ensure I survive.

It took seven years to get to this point — seven years to go seven miles. From seven miles down, back to the surface was 70 minutes. The sub was a rocket at that point and it felt like a train car. That’s the fastest I’d ever moved vertically underwater.

How difficult was it to stay still inside the submarine?

It seemed like just a few minutes and I’m going past Titanic depth and then I’m going past Bismarck (Germany’s sunken WWII battleship) depth, 16,000 feet. Then I’m going past the deepest any sub on the planet, other than our sub, can dive.

When I got to 27,000 feet, which was the deepest I had dived before, I still had 9,000 feet to go. Everything just stopped and it got really quiet. It was as deep as Mount Everest is high — with still two kilometres to go.

When I reached (the bottom), I just sat there and thought, ‘Here I am. Seven years and all that engineering and all that work and it happened.’ It just looked like somebody had rolled out white latex paint on a sheet of masonite. It almost looked like snowfields and it was really quite beautiful. There’s nothing like that moment when there’s nothing out in front of you but the ocean. Everything’s in order.

What did you bring back for research from the ocean floor?

I was looking for any animals that I could see, which I didn’t except for the little amphipods flying around in the water, which looked like little snowflakes. They were very tiny. The first thing I had to do was get a sample. So, I deployed the science door, deployed the (robotic) arm, got it out, pushed the core tube down. It looked like I got a good amount, brought it back up.

Is it true that you took a call from your wife Suzy while you were on the ocean floor?

Just about the time I hit the bottom of the ocean, my wife Suzy called. She had commandeered the communication system and she called me. So, here I am, in the most remote place on Planet Earth, that’s taken all this time and energy and technology to reach, and I feel like the most solitary human being on the planet, completely cut off from humanity, no chance of rescue, in a place that no human eyes have ever seen, and my wife calls me, which of course was very sweet, but let that be a lesson to all men. You think you can get away, but you cannot.

Did you plan the dive so close to the premiere of Titanic 3D to help the film’s publicity?

Interestingly, the day I was to attempt this, I had to go for my premiere for Titanic 3D. I had gotten two studios to step up and spend $20 million to convert Titanic to 3D, and I had to show up. It looked like the ocean was giving me a choice — I can either make the dive, culmination of a seven-year project, or I can go to my premiere. If I don’t go to the premiere, I’m going to have two of the biggest studios in Hollywood history not speaking to me for the rest of my life. But we didn’t come this far and not dive. So we had a window and I went in.

Other than fulfilling perhaps a personal dream, what did you want to achieve with the mission?

What I think this has done is (that) it shines a spotlight on the fact that there’s still a vast frontier here on Planet Earth that’s unexplored. Part of exploration is storytelling. In addition to taking the science data, the samples, you’ve got to take pictures and you’ve got to come back and you’ve got to tell the story. Not just the science story and not just the things the pictures are already telling you, but the story of what it felt like to go down there and to bear witness with your own eyes to something that nobody had ever seen before. That’s the true spirit of exploration.

What kind of footage will be shown in the Nat Geo documentary?

The Nat Geo special will chronicle my journey. It is a half-hour long.

Did you have a deep-sea exploration hero in your childhood?

I knew who Don Walsh (one of the two men who made the 1960 descent to Mariana Trench) was from my childhood — he was the deepest man in the world. The vehicle they were in was completely different in size, shape and the principles of operation compared to what I was doing. But it was incredible to have Don as part of my team. After the dive when I got out, the first person I see is Don Walsh, which is amazing.