Ralph and Peggy Burnet have amassed a world-class collection of art. They've adorned the walls of their Wayzata home with eye-popping work by some of the best known contemporary artists and have drawn curators from major international museums.

But their most dynamic piece of art may be the house itself: an 8,500-square-foot, all-white contemporary that looks more Malibu than Minnesota. The house and its 13 acres, which includes almost 1,000 feet of Lake Minnetonka shoreline, is on the market for about $25 million. And they've hired their son, Ryan, to sell it.

Now empty-nesters in their mid-60s, Ralph, chairman of Coldwell Banker Burnet and an owner of the Foshay Tower and the Le Meridien Chambers Hotel, and Peggy, who serves on the board of the Smithsonian Institution and has her own business interests, say they're ready to downsize.

"We're winding down," said Ralph.

So where will one of the biggest names in real estate move? The Burnets say they aren't in any hurry. They're considering a downtown condo or a place in the country, but they realize that even if they divide the property it could take a while -- perhaps years -- to find the right buyers for their unusual, art-filled house.

House as geometry

The Burnets' house may not be old, but it does have a history.

In the late 1960s, Ken and Judy Dayton convinced Italian architect Romaldo Giurgola to design a house on Wayzata Bay, one of the most coveted shorelines on Lake Minnetonka.

In contrast to the low-slung, one-level ramblers and ranch houses popular at the time, Giurgola worked in the International Style, a modern movement that tended toward height rather than depth. Considered a stellar example of its style, the house Giurgola designed was featured alongside Frank Lloyd Wright's famous Fallingwater in the book "American Masterworks: The Twentieth Century House."

The house sits in the middle of about 13 perfectly manicured acres on which the Burnets have assembled a menagerie of modern sculpture, including a one-armed metal gorilla (Peggy's favorite) and an installation of nine massive Corten-steel panels by Richard Serra.

The sculptural house is a collection of geometric shapes punctuated by a three-story tower and two chimneys at opposite ends. Its layout resembles a rectangle surrounded by triangles, circles and squares.

Roughly in the center is the 24-by-24-foot cube-like room that the Burnets use as their great room. A honed granite fireplace dominates one wall, and a massive painting by Damien Hirst covers another. Where the other walls would be are wide openings that connect to the rest of the house. Light spills into the space from windows that line the upper level of the cube and from the three-story tower. Even on a partly cloud day, the space is a kaleidoscope of sunshine.

"I love different kinds of light," said Peggy. "This whole room changes every hour."

Because the great room is set at an angle, the other main-floor rooms -- family room, dining room, gallery and kitchen -- have no right angles. There's a 16- by 32-foot gallery with glimmering Brazilian cherry floors that's connected to a huge foyer. With the exception of a heart-stopping view of the lake, the family room is warm, enveloping and intimate. The kitchen is not only unpretentious, but void of the oversized -- and often unused -- commercial appliances that are now requisite in million-dollar houses.

There is a sprawling serving area that caterers use when the Burnets are hosting an event and Ralph sometimes cooks meals on a gas grill just outside the kitchen. And, aside from a new granite floor and a paint job on the cabinets, the kitchen is largely as it was when the house was built.

Other spaces, however, are decidedly upscale. The dining room, which is defined by a long stretch of curved floor-to-ceiling windows, is where Peggy holds most of her business meetings. Upstairs, there are three bedrooms and his and hers bathrooms, one of which Ralph has claimed as an office. With its views of the lake and a marble-and-glass soaking tub that sits in the middle of the room, it makes a deluxe man-cave. The master bedroom is deluxe as well, with a sitting area, a fireplace and panoramic views.

"The sunrises are so divine," said Peggy.

Personal connection

Though the house and its collections may look like a suburban satellite of the Walker Art Center, it's clear that the Burnets consider them more than just commodities. Both Ralph and Peggy rattle off the names of the artists as if they were talking about one of their five grandchildren. They've also commissioned several of the pieces, including a work that's a visual narrative of their 40-plus years of marriage.

Because they bought the house when only Ryan, the youngest of their three children, was still at home, it wasn't their family house.

"This is our house," Peggy says, leaning towards Ralph.

Still, that doesn't seem to make letting go of it any easier. After living there for almost 15 years, the Burnets say the house always feels new to them because of the play of light, the way the many windows connect them to the changing landscape.

Ralph, who's spent decades in the real estate business, said he's yet to find another house that compares with this one.

And while Peggy said she's the kind of person who is always looking forward to the opportunity, the next adventure, she knows they're unlikely to find something quite as unique.

"It's the most thrilling house I'll ever live in," she said.

Jim Buchta • 612-673-7376