The magnificent $750 million Villa Leopolda in Villefranche-sur-Mer was built for King Leopold II of Belgium in 1902. The estate is so big that it requires 50 full time gardeners. The grounds cover 20 acres of garden and visitors can stroll amongst 1,200 olive, orange, lemon and cypress trees. In 2008, owner Lily Safra (wife of the deceased Syrian (Lebanon-born) businessman Edmond Safra), a famous Jewish philanthropist, decided to sell it. Russian billionaire Mikhail Prokhorov intended to buy it. After making a ten per cent down-payment, he then backed out of the sale after the global credit crunch hit. But a court in Nice later ruled that he had to forfeit the $75 million deposit he put down for the mansion. Prokhorov had signed a sales agreement for the Villa, and French law stipulates that purchasers lose their deposits if they pull out after such an agreement has been executed. But don't feel sorry for the guy, he is still worth a cool $17.85 billion.