Known as Xanadu 2.0 — a name inspired by "Citizen Kane" — Gates' home base is Medina, Washington, a wealthy suburb of Seattle that's home to many tech titans. Gates owns at least 12 parcels of land there, totaling about 10.5 acres.
Purchased for about $34 million between 1988 and 2009, the current combined assessed value of the Lake Washington-adjacent properties is $183.5 million.
Built into a hillside and accessible via a driveway that feels "like arriving at Jurassic Park," according to a former Microsoft intern, the estate, which took a reported seven years and $60 million to build, is home to a 2,100-square-foot library (with one of Leonardo da Vinci's notebooks on the shelves), a 60-foot-long swimming pool with an underwater sound system, and a room with a built-in trampoline. The primary residence has seven bedrooms and 18.75 baths, according to public filings, and there's reportedly a 20-car garage for his Porsche collection.
It was also built to be energy-efficient and technologically advanced, with a heating and cooling system that automatically adjusts to guests' liking and lights that turn on and off automatically as people go from room to room.
"My house is being designed and constructed so that it's a bit ahead of its time," Gates wrote in his 1995 book "The Road Ahead." It is made of wood, stone, glass, concrete, and "silicon and software."
"I'll warn you, though," he added. "When I describe the plans, people sometimes give me a look that says, 'You're sure you really want to do this?"
One of those people could have been his then-wife, Melinda French Gates, whom he married after he had already begun work on the house. While she changed his plans for the kitchen and added her own office space, she may have never warmed up to the house.
"We won't have that house forever," she told The New York Times in 2019. "I'm actually really looking forward to the day that Bill and I live in a 1,500-square-foot house."