(FORTUNE Magazine) – At Disney World, a land of predictable fun and scripted surprises, the creation of a $1 billion theme park starring 1,000 live animals--lions, tigers, rhinos, and gorillas, all with minds of their own--has raised some ticklish questions. Such as: How do you give stage directions to a giraffe? Well, here's how. Say you've transformed a Florida cow pasture into the closest thing to an African savannah this side of Nairobi, and you need a giraffe to stand right there--next to the rutted dirt road that will take guests, perched atop bouncy safari vehicles, through the bush. What you do is build a lazy Susan into an artificial baobab tree, hook it to a timer so it rotates slowly, and fill it with delectable acacia leaves--inviting the giraffe to enjoy a leisurely daylong feast. "That way, when people come by in the ride vehicles," explains landscape architect Paul Comstock, "there's Mr. and Mrs. Giraffe staring right in their faces, because the plants they like to eat, the candy, the Godiva chocolate of the plant world, are right there for the photo op. Bingo!" Another magic moment, manufactured by Disney.

Parents, get ready. Sometime soon, one of your little ones may approach you with a very important question: Can we go to Disney's Animal Kingdom? Ponder your answer carefully, because your child's status in the neighborhood may depend on it; some kid down the block will surely be part of the stampede to Orlando. In its first year, Disney expects seven million to eight million people to visit Animal Kingdom, the biggest, most ambitious, most expensive theme park ever built.

Nearly a decade in the making and five times bigger than Anaheim, Calif.'s Disneyland, the new park is the most important addition to Disney World--already the most popular tourist destination on earth--since Disney/MGM Studios opened in 1989. Since then the complex has grown furiously, adding 11,195 Disney-owned hotel rooms, a $100 million sports center, an after-hours entertainment district, even a wedding concession that has married 10,000 couples. Today's Disney World has something for everyone--budget hotels with $69-a-night rooms, tony eateries where dinner for two costs $150, classes in horticulture and animation, 99 holes of golf, convention space for companies like Lehman Brothers and Shell Oil. This isn't just a place for kids anymore; teen and adult visitors outnumber kids four to one.

The numbers add up to a big, growing, and highly profitable business for the Mouse House. Last year, Disney's theme parks and resorts generated $5 billion in revenues and $1.1 billion in operating income; revenues have grown by 51% and operating income by 76% since 1992. Profit margins are about 23%, better than for other Disney divisions, which post margins in the high teens. With the animated-movie market getting crowded and ABC television in a prolonged slump, Disney is counting on theme parks to drive future growth. "The division is clearly on a roll--even before the opening of Animal Kingdom," says Salomon Smith Barney analyst Jill Krutick.

The highly cyclical theme-park business has thrived during the strongest U.S. economic run in history, and Disney has benefited the most. The company towers over the industry, with the world's six most visited theme parks all bearing the Disney name. But rivals Universal Studios and Anheuser-Busch--which actually pioneered the animals-in-the-wild concept at Tampa's Busch Gardens, albeit on a smaller scale--are growing briskly too. Universal has begun building a second theme park called Islands of Adventure, plus hotels, theaters, and stores in Orlando, and it's opening a park in Japan in 2001. Just last week Universal said it will open an urban themed attraction in downtown Beijing, where Disney's still shut out. Disney, meanwhile, is adding a second park in Anaheim, another in Tokyo, and two Florida-based cruise ships. "All of those are billion-dollar-plus bets," says Judson Green, the president of Walt Disney Attractions, who has led the theme park division's rapid growth.

Synergy-obsessed Disney executives like theme parks not only for their financial returns but also because they complement the company's other businesses. Animal Kingdom, for example, will be home to live shows spun off from The Lion King and The Jungle Book. "In a way, we're an ancillary market, because we take our animated films and infuse them into our parks," says Green. More important, a family that's housed, fed, and entertained at a theme park takes home an indelible impression of Disney and its brand. "We're trying to create positive relationships that will last a lifetime," Green says.

That's why Disney has gone to extraordinary lengths to make Animal Kingdom a hit when it opens on April 22. Theme parks, after all, aren't movies, where if you produce a flop, you can sell it to cable or video and bury it. The Animal Kingdom consists of four million cubic yards of dirt, 40,000 mature trees, 60 miles of underground utilities, waterways, and structures built by, at peak, 2,600 construction workers. It's not going anywhere. "If we put up a new attraction and it's not successful," Green says, "we're stuck with it."

No wonder it took Disney 5 1/2 years to decide to build Animal Kingdom. Disney CEO Michael Eisner always liked the idea, but the swarms of strategic planners and MBAs who surround him did not. The park's largely the work of Walt Disney Imagineers, an eclectic group of designers, artists, writers, and engineers who have been recreating reality since Walt himself first sketched Disneyland.

Joe Rohde, 42, an outspoken, iconoclastic Imagineer who has led the design team since 1989, took the creative lead at Animal Kingdom. Rohde couldn't get hired in a Disney theme park--he wears a mustache and a cluster of earrings the size of a tangerine--and he disdains the guys in suits who opposed his idea. Says Rohde: "They went to zoos and reported back that there's one in every city, you pay three bucks to get in, they're subsidized, they're dirty, they're smelly, animals are in cages, people think they're depressing. How in the world is this a business we want to get into?"

Rohde and a small group of Imagineers quickly tackled the "zoo" problem. Sure, the park would have live animals, but they'd be showcased in a spectacular setting and be part of an unfolding story with a conservation theme. The park would also feature an educational area, like Epcot, about dinosaurs and traditional theme-park attractions where kids can enjoy rides and entertainment inspired by imaginary animals--mostly Disney characters, of course. Says Rohde: "It would be not merely live, real animals, but all the animals we know and love. So the park is really about us. It's about our feelings about animals." That vague sort of thinking allowed for all sorts of possibilities--as well as all sorts of uncertainties. "It always is more frightening when it's different," Eisner argues. "But that's what makes it worthwhile in the end."

The bigger problem holding up the project was that the theme-park business was in trouble in the early 1990s. The recession took a big toll, as did tourist murders in Florida and the southern California earthquake. From 1990 to 1994, the number of visitors to Disney World and Disneyland actually fell. Another negative: the disastrous 1992 opening of Euro Disney. "There was this whole concern about whether the theme-park and resort business was a good thing for Disney to be in," Green says. "The skeptics said that maybe this is a mature business, maybe we've hit the wall in Florida."

The park's backers tried every trick to win approval. When Eisner wondered whether the mere sight of animals would excite visitors, Rohde brought a 400-pound Bengal tiger into a meeting where the big cat brushed up against the CEO. That objection evaporated. The phenomenal success of The Lion King surely helped. Most important, though, as the economy perked up, so did theme-park attendance--and the financial results being delivered by Green.

It's easy to misread Judson Green. In a company where the tensions between off-the-wall creative types and traditional executives are palpable, Green, 45, dresses conservatively and often lapses into management jargon. The strait-laced former Eagle Scout from Illinois joined Disney in 1981 in the internal audit department. "I was an MBA and a CPA," he says. "Those aren't great sets of initials around here." Yet Green drove the theme park business to a new level by shaking up--indeed, loosening up--an operation that had become inbred, tradition-bound, and hierarchical. The old culture might not have embraced a theme park as unpredictable as Animal Kingdom.

Take, for example, the safari ride. Guests travel in 32-person vehicles driven by cast members who must react to what they see. Says Green: "They're part of the show. Can we rely on individual drivers to dispatch at the right time, and keep their eye on the guests? Are they going to be distracted by the animals? Are the animals going to be distracted by the vehicles?" Inevitably, there are risks, although well-disguised moats and fences ensure that the animals won't attack each other or the guests.

Green's proven willing to take risks. Since becoming president of Walt Disney Attractions in 1991, he's brought in senior executives from elsewhere and hired the theme parks' first outside ad agency. Overcoming Disney's deserved reputation as a difficult partner, he made deals with Cirque du Soleil and Black Entertainment Television to bring attractions to Disney World.

Most of all, he has given Disney World's 45,000 employees--the most people who work for one company, in one place, anywhere in America--some freedom to improvise. That, it turns out, is entirely in character, since Green is a spirited pianist and composer whose passion is jazz. He's released his own CD, and he anchored a jazz quartet at a recent training session for Disney World managers. The message: Take chances, perform solo, express yourself, be open, listen, and cheer your partners, all within an agreed-upon framework. This is partly about recruiting and morale in a tight labor market, but it's also about the way the business relies on thousands of cast members who touch the customers every day. "You cannot pretend to do these jobs well," Green says. "You have to feel it in your heart."

That may sound a bit precious, but Green contends that his analyses have found that attractions with high-rated leaders and cast members, who are held responsible for their performance, deliver the highest levels of guest satisfaction. "We have ways of measuring things you wouldn't believe," he says. Happy customers, he argues, spend more time and money at Disney World; the average cost of a one-day admission pass has climbed from $35 to $43 since Green took over, and hotel occupancy rates are at a healthy 90%.

The usual Disneyesque obsession with detail is evident throughout Animal Kingdom--even to the extent of purposely aging the brand-new park. Paint is cracked and faded. Potholes were built into the safari road. Boats were dented and given a coat of rust. Explains Rohde: "We created this motif of age, of erosion.... It reminds us that no matter how great our efforts, nature is the most powerful force around us, and we should respect it. It's almost a moral tale."

While theme parks are mostly illusion, occasionally things that seem authentic really are. Thatched roofs on buildings in a faux African village were hand-woven by 13 Zulu thatchers brought over from South Africa, using bundles of grass harvested back home by their wives, sisters, and mothers. Some 1,500 hand-painted wooden animals were crafted in Bali, under Disney supervision. The animals, of course, are real too, though they also get the Disney treatment. Take Hope, the gorilla who never flies coach. Last summer, Hope--who, to be fair, was pregnant at the time--got a chartered jet to take her from Chicago's Lincoln Park Zoo to Animal Kingdom.

Such treatment was less an extravagance than testimony to the price Disney had to pay to secure animals from the tight-knit zoo world. Only after Hope's keepers were assured that she'd get a loving home, not to mention Hollywood star perks, would they give her up. "Gorillas are like family to people," explains Rick Barongi, who left the San Diego Zoo to command the Disney menagerie. "This is like giving away your pet."

Eisner frequently jets in from the coast to tour Animal Kingdom and offer comments, like a network executive screening the pilot of a sitcom. Riding a boat in the Discovery River, he decided there wasn't enough to do. "It's a pretty sight," he says, "but what is the intellectual content? What could we do to make it exciting?" Much brainstorming ensued. The new, improved boat ride will now feature a cast member on board who will give guests a chance to meet and greet small animals like leeches and tarantulas. "It's expensive," Eisner concedes. "You're adding an extra person on the boat, and there are a lot of boats. But it's worth it."

Eisner helped shape the Animal Kingdom's Weenie--a Disney term for signature landmark, in this case a 140-foot Tree of Life sculpted in the shape of animals--and he insisted on a big Wow, meaning a thrill ride, here featuring lifelike dinosaurs. He's seen It's Tough to be a Bug, a multimedia animated show that will play in a 430-seat theater inside the Tree of Life, maybe ten times. During the movie--which promotes characters from A Bug's Life, a Disney Christmas 1998 feature--viewers will hear, feel, smell, even be sprayed by bugs, thanks to Disney's special-effects experts. "It may be the best show we've ever done," Eisner says.

The CEO-cheerleader is peddling his $1 billion investment everywhere. He'll host a two-hour ABC prime-time special about the making of Animal Kingdom. (Ah, synergy.) Then he'll throw an opening-day party for 14,000 invited media people, corporate partners, and travel agents.

This summer, Disney will launch its much-delayed Florida-based cruise ships, part of Green's bailiwick. Disney's California Adventure, a companion park to Disneyland, and Tokyo DisneySea, a next-door neighbor for Tokyo Disneyland, are scheduled to open in 2001.

Nothing's decided beyond that, but Eisner and Green are playing with lots of ideas. Maybe another big bet in Orlando, a high-tech Wide World of Sports theme park, neatly synergized with Disney's ESPN, with fantasy games and thrill rides. (Time Warner's Atlanta Braves already decamp for spring training at Disney World.) Probably another park in Europe, where Disneyland Paris is finally making money. China? Sure. Latin America? Why not? Says Green: "In the not too distant future, we'll find another place to plant a flag." For now, though, get in the mood for animals. Lots of animals.