12. XANADU 2.0 – SEATTLE
Source: theclever.com, youtube.com
Estimated Worth: $ 125,5 million
This awesome mansion is the living quarters of the second richest man on Earth, Bill Gates. A 60-foot swimming pool with an underwater music system, 2500 square foot gym, heated floors and driveways, 2100 square foot library are just some of the features that set this mansion close to the top of this list.