Roger Blakey Photography

Don't let your eyes deceive you. This isn't Narnia, although many first comers to these beautiful ice castles can't help but think of it.

Artist Brent Christensen, 50, of Alpine, Utah, has spent the last four years perfecting the craft of intertwining icicles into solid, 20 to 25-foot-tall structures he calls ice castles.

The hobby first started in 2000, when Christensen's family moved from sunny California to chilly Utah, and were looking for fun outdoor activities to do during the winter.

"We started doing winter stuff in the yard, playing around with the kids, making igloos and ice forts and slides and stuff," Christensen told ABCNews.com. "And it just evolved. One year I stumbled upon the concept of doing icicles by spraying water.

"We made one with a big wooden frame under it, and when it melted in the spring, it was a huge mess with a pile of soaking wood. The following year I didn't want to use any wood so it would just cleanly melt away. During the course of that winter, I stumbled upon the concept of fusing icicles to make a lattice to spray water on and build upon."

Once he got really good at building the ice fortresses, he approached several nearby resorts to see if they'd be interested in having him build displays for their guests. There weren't any takers at first and Christensen began to give up on the idea. Then, several weeks later, he heard from the manager of a small local spa and resort.

"The manager was like, 'Yeah, sure, let's do it next year. That was the opening door that got us into the public level," said Christensen.

Since then, Christensen has become famous for his magnificent structures. He currently has two ice castles on display this year, one in Steamboat Springs, Colo., as well as a larger, more grandiose one he created in the parking lot of Mall of America near Minneapolis-St. Paul.

"People come and they pay an admission and spend about a half an hour usually taking pictures and exploring," he said. "The ice castle itself is probably about an acre and a half."

Christensen, along with his team of about 20 men, worked around the clock for two weeks prepping the Mall of America ice castle, which opened on New Year's Eve, making it perfect to open for the public.

"We're pushing 20 to 25 feet tall in some spots," he said. "The goal is to eventually to go 40 to 50 feet. We get to a point where it's something the public's going to enjoy, then we continue growing it."

It's an evolving process all throughout the winter months, with Christensen constantly adding, re-shaping, and building bigger and better icicles to complete the castle.

"Most people have never experienced anything like it because it's so different. For me and my guys now, even for us who've done it for a couple years now, after the water's been running at night, it's still fascinating."

There is no set "closing date" for the ice castles. Christensen said he just keeps his eye on the extended weather forecast, and when temperatures stay in the high 30s toward the end of February, he'll begin to dismantle the pieces of ice, move them into safe piles at one end of the parking lot, and let nature take its course, melting his ice kingdom away.