The Homes of America's Billionaires

As an adjunct to their just-released annual list of the 400 richest Americans, Forbes has included a special report on the homes of some of the billionaires who made the cut. Capping the account is of course Bill Gates, who tops the 400 with his $57 billion fortune. It's hard to say exactly how much his high-tech 66,000-sq.-ft. house on Lake Washington near Seattle is worth. The property includes a 60-foot swimming pool with an underwater music system, a domed library with two "secret" bookcase doors and a 1,000-square-foot dining room, the mag notes.

Also featured: the historic seven-story Duke-Semans mansion (above) in Manhattan owned by cab driver-turned-mogul Tamir Sapir (net worth $1.9 billion), who bought it from Doris Duke's relatives for $40 million after a single walk-through. He's now said to be spending $10 million on renovations. And then there's Oracle co-founder Larry Ellison's (net worth $27 billion) 23-acre estate in Woodside, Calif., "reminiscent of a 16th-century imperial Japanese palace" which reportedly cost over $100 million to build. You can see a slideshow of these megamansions and more here.