1. Palo Alto Chateau
This French-style chateau in Palo Alto, CA, was the most expensive single-family home purchased in 2011 when Russian billionaire Yuri Milner snagged it last March for $100 million. It’s also one of the most expensive homes ever sold in the U.S (Donald Trump sold a Palm Beach mansion for $100 million in 2008). Milner, the 49-year-old founder of investment firm Digital Sky Technologies and a major investor in Facebook, reportedly plans to use the 25,500-square-foot home as a secondary residence. The estate comes with a ballroom, spa, wine cellar, views of the San Francisco Bay, five bedrooms and nine baths (which, for the price tag, almost seems skimpy).