Microsoft Co-Founder Paul Allen Buys Another Home on Mercer Island

Some people collect cars. Microsoft co-founder Paul Allen collects homes. Last month, he bought another house on Washington's Mercer Island. While the $5.4 million house is pricey, Allen loves its location. His latest acquisition brings the number of residences he owns (that we're aware of) on Mercer Island to 11.

Allen, one of the world's richest men, also has a $25 million house on "Billionaire's Beach" in Malibu.

Allen sails the seas in one of the world's largest yachts, Octopus, which comes with a submarine that he loans out for research projects. He also owns the NFL's Seattle Seahawks and the NBA's Portland Trail Blazers.

Allen clearly has a soft spot for the area where he grew up. The Seattle-born Allen, 62, made his billions with his boyhood friend Bill Gates in Microsoft.

After being diagnosed with Hodgkin lymphoma, Allen left the company. When the tech innovator beat his illness, he began " living large," according to Forbes. With an $18 billion fortune, Allen is ranked No. 26 on the Forbes 400.

His newest house on Mercer Island is a1948 bungalow, which measures 3,320 square feet. It has four bedrooms and four bathrooms.

While Allen keeps a 10,000-square-foot estate -- featuring a helipad and concert hall -- for himself, his other homes on the island are guesthouses, including one just for his mom, according to Curbed.