Location: Lake Washington, USA

House area: 66,000 square feet/6,100 square metres

Site area: 5 acres

Description: Spread over 5 acres of lakeside real estate, the Gates' sprawling estate is one the the most expensive and high-tech ever built. The estate contains a pool building, exercise facilities (including sauna, steam room and a trampoline room), library, theater, offices, guest houses, underground garages, a boathouse and an activties building with putting green and various sports courts.

The main building is predominantly timber frame, sitting on earthquake resistant concrete piers. Over half a million feet of timber was used in its construction. The house also contains miles of fibre optic feeding each room in the house from a central server room. Touch-sensitive pads in each room control lighting, music and climate, and visitors wear electronic pins which automatically adjust settings such as lights and music to their preferences as they move around. Even the 60 foot long indoor swimming pool as a sound system that lets you enjoy music underwater.