A stock trader and his wife quit their day jobs to set up the UK's biggest Christmas grotto. This year the business will earn almost $30 million

This year, their holiday-focused business is on course to rake in around $30 million in revenue.

Back in 2007, the couple launched Lapland U.K.—an immersive Christmas experience for families that pops up in an English forest for six weeks each winter.

Over the years, they’ve drafted in Hollywood set designers, hired troupes of actors and carefully crafted dozens of Christmas characters—each with their own detailed backstories—to stage four-hour visits to “Lapland” that include ice skating, toy making and, of course, a meeting with Father Christmas.

Since its first year, Lapland U.K. has welcomed more than 1 million guests, including royalty and A-list celebrities like Elton John and the Beckhams. Tickets for this year’s extravaganza—which were priced between £59 ($72.50) and £149 ($183) each for everyone over a year old—sold out months before its doors opened on November 11.

The Battles came up with the idea for Lapland U.K. after Alison, a former elementary school teacher, was left disappointed by the lackluster holiday experiences on offer for her own four sons during what she labels their “wonder years.”

“I was very passionate about giving our sons lots of magical moments they could cherish and remember,” she tells Fortune. “During our boys’ years of belief, we visited pretty much everything that was out there—department stores and steam trains and stately homes, and everything in between—but we never found anything that I felt matched the importance that I placed on this moment.

“It was always very trivialized and commercialized, and I couldn’t understand why this moment that was so precious to us as a family wasn’t really being respected and properly honored.”

Alison and Mike have dedicated their lives over the past decade-and-a-half to filling that gap in the market. From the beginning, they wanted young children to truly buy into the illusion that Lapland U.K. is a real, magical place that’s home to Santa and his elves.

That endeavor has seen them scouring antique markets for props—the couple say they “don’t do plastic” in a bid to be sustainable and preserve their “creative integrity”—publishing in-depth story books about Lapland U.K.’s residents, and spending weeks in rehearsals every year to ensure the kids who visit can’t poke holes in the magic.

They send a personalized wax-sealed invitation to children in advance of their ticketed arrival date, while parents are asked to secretly fill out a questionnaire about their child before the visit so that Father Christmas can speak to them in detail about their likes and hobbies.

While it might seem fair to assume all of this came naturally to Alison—who says she loved her job as a teacher so much that she “couldn’t believe someone was paying me to do it”—Mike’s former professional life looked vastly different to fraternizing with toymakers at the North Pole.

Before Lapland U.K. came into existence, he spent years working in London’s financial epicenter. But despite building a “reasonably successful” career as a stock trader—one that saw him headhunted by Goldman Sachs (an offer he declined)—Mike’s true passions lay elsewhere.

“As a child, I was always quite gifted with art—I could paint, I could draw, I was creative,” he explains. “But coming from a traditional family, my father sort of sent his son off to the city to make some money, so all of that was put away.”

While his heart wasn’t 100% in the finance industry, Mike says he’s grateful for the experiences he gained on the trading floor, which have been “fantastically useful” in his second career.

“I had a good career in the city. I started off working in various banks, I went down to the stock market floor, I became an independent trader,” he tells Fortune. “One of the things I learned was how to risk large amounts of money, and how to embrace and be at peace with that.”

Mike adds that in his past life as an investor, he became “very vision-based,” which has helped him “see what could be possible before we get there” with Lapland U.K.  

“But what was really special for me on my own journey is that all the creativity I had put away and bottled, once the cap came off of it, I’ve found myself directing the show, being across the narrative of the stories that Alison and I write together, and everything and anything,” he tells Fortune.

‘It’s a risk, but you can change your life’

His passion for the project didn’t stop him questioning himself for taking the leap, however.

One of the major challenges the couple, particularly Mike, faced in the beginning was convincing others—and themselves—that what they were doing was worthwhile. When they did let people in on their vision, they remember being met with skepticism and bemusement.

“When I gave up the ‘grown up’ job that I was doing, I used to question whether I’d gone mad—I was thinking that I’d lost the plot to be doing this, even though in my heart I believed that this subject deserved so much better than it was getting,” Mike says. “But I used to look in the mirror and wonder if I’d gone nuts and didn’t even know I was nuts.”

Alison recalls being embarrassed to tell their next-door neighbors about the business when they first came up with the idea.

“I was almost afraid of the response we’d get because it seemed like you’ve gone off to join the circus, in this very trivialized sense. But we were, from the beginning, really passionate,” she says.

“People were like: ‘You’re giving up this great career and money and all this clever stuff that you do to go and work with Father Christmas and try and make a great experience for children. Is that right, Mike?’” Mike adds.

But he describes switching the stock market for stockings and Santa Claus as “going back to my origin story.”

“I’m more me now than I’ve ever been—and I’m better and happier because of that,” he says. “It’s a big risk, big jump off the cliff thing, but it can be done. You can change your life, and some of the skill sets that you’ve probably picked up in a previous profession definitely can be a value in a new one.”

Rejecting investors

Part of that risk involved refinancing their home and borrowing money from friends and family to fund the launch of Lapland U.K.

While they’ve had offers from would-be investors, the Battles have opted to keep the business firmly within the family—and have continued to reinvest the profits back into the company to ensure this remains the case.   

“I always think of money as like a person, and they’re saying, I want this and I want that, and that might not be aligned with what is best for the business,” Mike explains. “For me, it was more or less, just leave me and Alison alone. Our agenda was aligned: just make it brilliant. That was our agenda.”

Alison agrees that not compromising on their vision is a huge part of what made Lapland U.K. so successful.

“Don’t compromise: say no to most things, because saying yes is going to compromise getting to your North Star,” she advises budding entrepreneurs. “We said no to virtually every approach along the way because we didn’t want any sort of pressure on us to compromise.”

Mike points out that sixteen years later, Lapland U.K. is still 100% family-owned—and two of the couple’s sons are now working full-time within the business, working on brand management and digital development.

“If you have an investor, they’ll be saying, we want our money back in three years’ time, and we want this and that, and your exit strategy,” he says. “We own everything, and there’s complete integrity, and I think that’s one of the reasons we’re proving to be so seductive to the public—because there’s real integrity in what we’re actually trying to do.”

Looking ahead, the couple sees a big future for their Lapland business, including possible international expansion and more widespread adoption of the Father Christmas narrative as told by their books.

“Our purpose is to honor childhood together,” Alison says. “We are doing it with the families, not to the families—we’re facilitating this world for them. So, I think our future really is just to spread the story to as many families as possible.”

For now, that means welcoming 170,000 people to their hidden world in Swinley Forest between now and the end of December.

“This should be the most amazing celebration, you lay down these memories that you’ll have for the rest of your life,” Mike says. “We’ve got to be a game changer—it can’t be just a little bit better than what anybody else has done before. We want to be the iPhone of Christmas experiences.”