Producer/Co-writer Cooper Layne was on a visit to Hawaii when he saw magma from a volcano flowing down into the ocean and cooling as it hit the water.

"I thought, wouldn't it be interesting if you could actually go into a volcano in some kind of a ship that could take you to the molten center of the earth?" Layne recalls. "And then I realized that the molten center of a volcano is really a spigot directly into the liquid core of the planet."

Thus, the idea for "The Core" was born, and once he had a completed screenplay, Layne took it to producer David Foster.

With over 25 production credits to his name, ranging from classics like "The Getaway" and "McCabe & Mrs. Miller" to more recent hits like "The River Wild" and "The Mask of Zorro," Foster knew a great script when he saw one. He went to his friend, director Jon Amiel, with whom he'd wanted to work for years, and the intriguing story clinched the deal.

The next order of business was to assemble a topnotch cast, so Foster and Amiel sent out the script, which they felt would attract the high caliber actors they were looking for.

For Eckhart, the movie's "reluctant hero," it was not only the captivating script that interested him in the project, but also the chance to make a film everyone, including his kids, would enjoy.  "This film is about people working together to save the planet," says Eckhart. "Not only am I proud of it, but I think it will get people thinking about our earth in a whole new way."

Stanley Tucci, who portrays the know-it-all scientist, was impressed with the script's balance between character development and action. "This is a really good ensemble piece in which everybody is able to show off his or her talents and have a good time. It will definitely make you think."

"This film has everything," observes Eckhart. "It has humor, a little bit of romance and a lot of heroism. And it definitely covers new ground."

"The most enjoyable part of the film is how people of very disparate natures overcome tremendous obstacles," says Tucci. "They have to call on different parts of themselves that maybe they've never called upon before."

Scientists, including Albert Einstein, have puzzled over the Earth's magnetic field for decades, and Einstein himself claimed that it presents "one of the most important problems in physics." Dr. Sten Odenwald, a Harvard Ph.D. in Astronomy concurs. "If the magnetic field of the earth suddenly changed, and this does happen naturally every 250,000 years or so, the consequences would be fascinating," says Odenwald. "Already geophysicists have begun to notice a decline in the strength of the earth's magnetic field. We don't really know if the decline is just a natural ripple, or the portent of something far more sinister."

In fact, it is this very unknown aspect of the film's subject that makes "The Core" not just another science fiction movie. Says producer David Foster: "We've seen sea adventures and space odysseys, but traveling into the core of the earth is largely unexplored territory."

Though inspired by both real and extrapolated science, "The Core" is ultimately driven by imagination. As director Jon Amiel points out, "Even the scientists can only speculate what's down there. They beam sound waves into the earth, and by the ways in which those sound waves are refracted, they can guess that there is an outer liquid core and an inner solid core of nickel and iron. But nobody knows for sure. Basically, the film is science faction: a little bit of science, a certain amount of fact and a lot of fiction."

Something else that scientists don't know for sure is whether the earth's core would ever cease to function. Intense controversy still swirls around the core of our planet. Is the heat that it generates a product of cooling nickel and iron, or is there, as one theory suggests, a giant five-mile wide nuclear reactor of plutonium and uranium burning below us? Why do the magnetic poles seem to shift every 500,000 years or so?

"We used to think that space was the last frontier," says Amiel, "but there are actually enormous and unfathomable mysteries just a couple of thousand miles below our feet. One of the questions I think the movie asks, in a very interesting way, is what if you, an ordinary person, were thrown into a situation like this? Would you be a hero? What strengths would you bring to the task and what strengths might you be surprised to discover?"

"Jon Amiel really wants the audience to care about the people," observes Delroy Lindo. "He has a very well-placed concern that the special effects in the film not override the human beings in the story."

Keeping the action tense and exciting, while at the same time exploring the dynamics of the crew inside the ship, is definitely of primary importance to Amiel.

"Character conflict is the stuff of all good drama," says the director. "You take this unlikely group of people -- a career NASA commander, a take-charge astronaut, a very attractive, dynamic woman who is the youngest female ever to go into space, a French nuclear physicist, an arrogant scientist and his colleague with whom he's had a 20-year rivalry -- and you have an absolutely perfect recipe for a wonderful, rich character brew."

Turkish born Tcheky Karyo, who plays the French Leveque, points also to the multiracial element inherent both in the ship's assembly team and its ethnically diverse terranauts. "There are cultural differences," he says, "but human beings are human beings all the same. And you need all these different people to save the world."

The design team found that creating the world of inner earth was a task with unlimited possibilities, yet oddly constrained by the expectations of the audience.

"The dilemma is you have to make things look like people believe they should, not necessarily as they really are," explains Gregory L. McMurry, visual effects supervisor. "So you have to ask yourself, what will an audience imagine inner earth looks like, and then create it."

With this creative task, two issues emerged: past treatments of inner earth and limited knowledge among scientists about the earth's core. Referencing the Jules Verne classic, Journey to the Center of the Earth, and the 1959 movie it inspired, Jon Amiel says, "Jules Verne envisioned a bunch of dinosaurs, a giant lake and the lost city of Atlantis in the center of the earth, but we're going for a slightly more realistic approach." "Our film isn't about finding monsters or anything like that," adds McMurry. "It's about real science. But because the information on inner space isn't as extensive as it is for outer space, we took a little bit of reality and stretched it as far as we could to make something that's believable but still a fantasy."

Director Jon Amiel believes that audiences will have as much fun watching it as everyone had filming it. "No matter what, it's an exhilarating ride that's going to take people into a world they've never seen before."