ATLANTA • The master and guest bedrooms in this house have doors that can withstand fire from an AK-47 assault rifle.

No, the property does not belong to a Russian billionaire or a Middle East royalty. Instead, it is located outside Atlanta, where the cream, colonnaded facade of Rice House, situated on 1.4ha, also shields residents from stress with a private theatre, bowling alley and infinity pool.

The car vault is large enough for 30 vehicles and has an entrance concealed by a waterfall.

Secret doors lead to a 15,000 sq ft bunker in which an embattled owner could conceivably hole up for years, with off-grid power and water drawn from three artesian wells drilled 304m into the ground.

The house had its own security architect who spent two decades designing secure buildings for the country's Department of Justice.

"This is a home where you could put a US$20-million painting on the wall and sleep comfortably at night," said listing broker Paul Wegener of Atlanta Fine Homes Sotheby's International Realty. "The same goes for your family."

The entrepreneur who owns Rice House spent six years to build his 36,000 sq ft fortress of an estate, said Mr Wegener.

It was just relisted for US$14.7 million (S$20.1 million), a drop from the original US$17.5 million.

The estate also needs to be finished, which Mr Wegener estimates would cost an additional US$3 million to US$5 million.

The owner planned Rice House - which comes with eight bedrooms, three kitchens, a private museum and an indoor shooting range, among others - as a family legacy, only to learn that his son was not interested in living there.

Instead of layering on the finishes appropriate to his collection of 18th-century furniture, he left a blank canvas for the next owner.

To construct the foundation, workers dug down to bedrock and then bored down into it. The walls are made from extra-strength concrete reinforced with rebar.

The car vault was initially designed with 18 columns. But the owner pushed back until engineers figured out a way to use custom-made bridge beam so no pillars would be needed to support the ceiling.

The house is highly energy-efficient, with geothermal heating and cooling and a solar energy system.

Though it is not stated in the listing - to maintain that hush-hush feel - Rice House is in Country Club of the South, a manicured, gated community in Alpharetta, Georgia, about a 30-minute drive north-east of Atlanta.

Homes in the 733-unit sub-division range from the high six figures to millions.

Over the years, a number of celebrities have reportedly owned homes in Country Club of the South, among them retired Atlanta Braves baseball pitcher Tom Glavine, singers Usher and Whitney Houston as well as National Basketball Association Hall of Fame sportsman Allen Iverson.

BLOOMBERG