Perched on a hill, surrounded by a limestone wall, sit two of the most remarkable houses in St. Paul.

The look-alike structures have a fairy-tale quality, with the same Cotswold Cottage-style architecture and undulating shingle roofs. And the enclosed walkway that connects the two houses on the second floor (a foreshadowing of the modern urban skyway) makes them appear, at first glance, to be one enormous house instead of two large ones.

"It looks like a little English village," said Dave Duddingston, who owns one of the houses.

Brothers Benjamin and William Goodkind built the Elizabethan twins in 1910, hiring Reed & Stem, the architectural firm behind the University Club on Summit Avenue and Grand Central Terminal in New York.

The brothers, president and secretary/treasurer for the Mannheimer Brothers downtown department store (later bought by Dayton's), were presumably close. Their walkway, which they reportedly called "the passover," gave them sheltered access to each other's homes.

The walkway had long been sealed off in the middle by the time Duddingston and his spouse, Clay Halunen, bought Benjamin's house almost 16 years ago, charmed by its distinctive architecture and private setting.

At 9,700 square feet, plus a carriage house with three stalls and living quarters underneath, it was a lot of house. Duddingston and Halunen upgraded all the systems — heating, plumbing and electrical — then worked with interior designer John Lassila on a redesign to complement the home's Tudor architectural features, including refinishing all the wood floors.

The lower level had been turned into a rental apartment. But Duddingston and Halunen had another use in mind.

"We were looking for a family room to watch TV," said Duddingston. "The other rooms are fairly formal rooms and not conducive to a big TV. It was an obvious choice for a man cave." They converted an old smoking porch into a spiral staircase leading to the lower level, and removed plaster to expose the limestone walls, then added custom built-ins, in-floor heating, a new bath and sauna, and a wine cellar.

In the kitchen, Duddingston and Halunen made updates, but were careful to maintain its commercial workhorse character, as befitting a space originally designed to be used by servants. (They did convert a servants' room into a breakfast room.)

About 11 years ago, the couple decided to add a swimming pool. Because their home is listed on the National Register of Historic Places, they had to use materials in keeping with the house, including vintage-look tile and stone retaining walls. "It couldn't be modern. It had to look like perhaps it was original to the house," Duddingston said.

Yet some things remain as they were. The kitchen still has its original butler's pantry with stainless-steel sink, and its original icebox. "People are fascinated by it," Duddingston said.

And off the boiler room, there's a bomb shelter.

"It was added in 1950, we think," said Duddingston. "It has not been touched." Inside are cans of food and boxed water, plus a toiletry kit with a bar of Dial soap and a tube of Colgate toothpaste. "Owners over the years have left it like a museum piece."

Duddingston and Halunen have loved living in their house, but they now own a lake home. "On nice weekends, we go there. We're not using the pool as much." So they've put the house on the market for $2.35 million.

The nine-bedroom, six-bathroom house has six fireplaces, three of them working. There's also a professional greenhouse, with lighting and temperature control. Oh, and half a skyway, which they use as a workout room.

"The house has defined our lives," said Duddingston. "It's so unique, and generates so much interest. We got lucky to have it."

Dave Duddingston, 612-221-5422, and Dan Duddingston, 612-221-4398, of the Duddingston Group, Keller Williams, have the listing.