House-shopping millionaires can almost always have their pick when it comes to real estate, whether it's a sprawling Georgia manor or space in a ritzy D.C. suburb.

But a new mega-mansion is soon to hit the market with a price tag only the super rich can afford: $500 million. When it goes on sale, it will become the most expensive house in the United States, eclipsing the Chartwell estate, known as the setting of "The Beverly Hillbillies" and currently on the market for $350 million.

Dubbed "The One," the 100,000-square-foot estate, located in Los Angeles' Bel-Air neighborhood, was designed by luxury real estate developer Nile Niami, who set out to build the most extravagant home in the U.S.

Construction on the house began in 2013 and is expected to finish next year. However, Niami gave CNBC's "Secret Lives of the Super Rich" exclusive access to the building site.

The opulent structure sits high above L.A. on four acres of land, offering incomparable views of the city's skyline. "In one eye-line, you have from downtown L.A. to the ocean to The Getty [museum]," Niami tells Robert Frank of "Secret Lives."

Take a look inside, via computer-generated renderings of what the finished product will look like.

The building will only feature the highest-quality materials, including a mountain's worth of marble.