Gates owns several horse ranches. Pierre Suu/Getty Images, Barry Estates With a net worth that's estimated to be as much as $80.1 billion, Microsoft cofounder Bill Gates is the richest man in the world.

Gates has exactly the kind of real-estate portfolio you would expect from a billionaire, from a Washington mansion worth $123 million to multiple horse ranches across the US.

Gates has also made several secretive purchases through his ultra-private investment firm, Cascade.