How These Amazing Ice Castles Are Built in Lake Geneva

Brent Christensen is an inventor. And a builder. About 10 years ago, he figured out how to fuse icicles together, a “light bulb moment” that led to creating castles entirely of ice, up to 30 feet tall in parts. All lit up, they look like something out of Disney’s Frozen. One of the six frost fortresses his teams will sculpt this winter is going up at Geneva National Resort in Lake Geneva.

THE FIRST THING we do is lay out irrigation lines similar to what you might have under your lawn. Then we put in all the outdoor power lines and waterproof-underwater lights; they’re lifted off the ground so the castles can grow around them.

Once the weather turns cold, that’s when we start spraying water all over the place. To grow castles, we prefer around 10 degrees. To maintain, we prefer below freezing and not too sunny.

Also on-site we have an “icicle farm” where we grow 5,000 to 10,000 icicles per night. One of the ways we grow icicles is on crisscrossing-wire racks hoisted on tall wooden legs – they look like horizontal chainlink fences. By spraying water over the top, icicles form below like stalactites, which can be harvested and fused into the formations.

After a week or so, the structures could be 10 feet off the ground. Then we’ll climb up and put more icicles onto it. After a month, the castle will reach the stature we want.

To clear out the walkways, we crush the top layer of ice with tillers, smaller versions of what construction workers use to break up asphalt. Once we’re done, the crushed ice is akin to gravel or sand. If it’s warm, we just need to be extra attentive to keeping the floors groomed.

Around March – or earlier if there’s an extended stretch of temperatures above 40 during the day – we dismantle. Typically that means bringing in an excavator – you don’t want people climbing on the castle when it’s not open.

And then we just let it melt.