In late December, Ice Castles’ creator, Brent Christensen, and a team of ice artists will finish transforming more than 12,000 tons of ice into full-fledged castles. With multiple large towers and ice walls, visitors are totally surrounded by the organic shapes of shimmering ice as they explore tunnels, courtyards, and caverns. In daytime, the castles glimmer in the sun; come nightfall, thousands of LED lights create an ethereal glow from within.

Today, the castles delight visitors of all ages, but the idea came from Brent Christensen’s winter playtimes with his kids. They had already made ice rinks, ice caves, and other chilly creations when Brent decided to build a fort entirely out of ice, using icicles as the base structure. The kids dubbed the structure an “ice castle”—and it started to look more and more like one as Brent added a cave, tunnels, and a slide that spilled onto an ice-skating rink. Eventually, cars started detouring to their block to drive past the creation, and local snowmen inquired about home prices. But the idea truly took off when a local resort asked him to build a larger ice castle for them. He’s built ice castles every winter since, including one in the winter of 2010–2011 that was featured in the Denver Post and called “a frosty, fairy-tale-like landscape” by the Los Angeles Times.