Walking down North Dearborn Street, the Thompson house would be hard to miss. Built in 1888 in the Richardsonian Romanesque style, it stands out even among Gold Coast’s myriad impressive mansions.

Walk through the front door, and you’d guess nothing has been altered, from the wood paneling to the intricate millwork.

But in truth, there’s nothing historic about the gut-renovated interior.

“My client bought it in 2009 and the house really was in bad shape,” says Tatiana Miller, a real estate broker with Coldwell Banker.

Now, after hitting the market as a pocket listing last May, the home is listed publicly for $21,900,000.

The Thompson house was originally built for the prominent attorney John Howland Thompson in 1888 by the architecture firm Cobb & Frost.

According to the Art Institute, the home was built out of “red rock-faced sandstone” with steps that lead "into a porch massed with windows on both sides, which are flanked by the usual grouped columns sharing foliate carved capitals.”

Thompson’s family owned the home until 1907, when railroad magnate Edward T. Jeffery bought it. It stayed in Jeffery’s family until 1938, when the Scottish Rite Cathedral bought it, along with two other mansions on the block, to use as offices.

Finally, in 2006, the Cathedral sold all three mansions to developers. The home’s current owner purchased it for $3.128 million in 2009, despite a dirty facade and decrepit interior.

“When we got inside, I saw there was beautiful millwork,” says Miller. “But everything was in bad shape and the floor plan was not accommodating for the modern lifestyle.”

And so, Miller’s client gutted the Thompson house and started over, a process that eventually took nine years.

Though the home was rebuilt to look old-school, there’s nothing dated about its technology, which includes an elevator, heated floors, built-in speakers, smart-control HVAC, and all sorts of other smart home gadgetry.

The home’s new 13,400 square foot interior boasts six bedrooms and just as many bathrooms. Enter through the front door and find the parlor decked out with mahogany paneling, hand-carved columns, Turkish Botticino marble flooring, and a fireplace.

Continue into the great room and you’ll find a crystal chandelier, silk wall coverings, and a wood and onyx fireplace. Upstairs, in addition to the master suite and other bedrooms, is a library.

The basement, previously unfinished, now dons a bar and wine cellar. There’s also a spa with marble walls, a dressing room, steam and sauna suites, and (why not?) a waterfall.

“With a clean palette, my client could have done anything,” Miller said. “But [they] wanted to bring the exterior inside.”