Money

This $185 million mansion has hidden rooms and an underground lake—take a look inside

Switzerland's St. Moritz ski resort serves as a winter playground for the ultra wealthy.

And within the resort sits the most expensive house for sale in the country, on the market for $185 million. As featured on a recent episode of CNBC's "Secret Lives of the Super Rich," the lavish home includes everything from a hidden library to an underground lake.

"This castle was designed to make a billionaire's jaw-drop," luxury real estate broker and listing agent Senada Adzem tells "Secret Lives of the Super Rich."

Let's a take a look inside.

Hidden behind the estate's relatively modest stone and glass facade, the winter getaway houses seven floors centered around a massive six-sided staircase, which serves as the home's backbone. The staircase itself is a feat of engineering — it shows no visible support beams.

SENADA ADZEM

Thirty-five-foot floor-to-ceiling windows frame the grand reception area, providing unparalleled views of the Swiss Alps.

SENADA ADZEM

On the other side of the room, a plush wall is covered top to bottom in mink fur.

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A wall in the reception area slides away to reveal a sleek library, sheathed in crimson velvet. A secret switch in the room reveals yet another hidden room, this time a covert office.

SENADA ADZEM

Every breakfast feels opulent in the mansion's egg-shaped breakfast nook, where the walls are adorned with 24-karat gold. A custom-made egg sculpture worth $145,000 hangs from the ceiling.

SENADA ADZEM

Crystal-clear glass stairs lead to five bedrooms with cashmere-covered walls. The adjoining bathrooms each feature a different rare stone, such as zebra-striped marble.

The master suite has a floor swathed in white Scandinavian fox fur and its windows look out onto a $1.8 million sculpture. A 360-degree shower sits in the center of the onyx-encrusted master bath. The highlight of the master suite, however, is the walk-in closet, coated in 24-karat gold.

SENADA ADZEM

The subterranean floors beneath the master suite house a wine cellar and a home theater worth $1.3 million. But the true star is the ski den, where the estate's billionaire owner has ski-in/ski-out access to a private chair lift.

SENADA ADZEM

After a day on the slopes, guests can retreat to the home's spa level, which is complete with a Himalayan salt chamber, steam room and high-tech shower that can be programmed with a multitude of settings and colors.

Even further down lies an underground lake, illuminated by Swarovski crystal lights. The ceiling reflects Venetian artwork and the walls are made of a mirrored Italian art installation.