Home comforts: the house that Bill built

The Gates family home is a 40,000 sq ft mansion in the exclusive suburb of Medina, on the shores of Lake Washington. The "lodge" has a library, with a domed reading room, a pool, a garage with enough space for 30 cars, speakers hidden beneath the wallpaper, portable touch pads that control everything from TV sets and the lights to the temperature. The total value of the house is estimated at $113m – the annual property tax is just over $1m.

It took seven years for the Gates mansion to be constructed and much of the house has been built underground, into the hillside. The house was originally the ultimate bachelor's pad, with a trampoline room, a cinema with a popcorn machine and so many gadgets that Gates' wife Melinda described it as like living in a videogame. Shortly after the wedding, Melinda got her own architect in and changed the house into a tranquil family home for them and their three children, with more cosy spaces and fewer boys' toys.

"The home has a stillness to it," Bono, a family friend, has said. "It's got a sort of Zen-like quality."