Villa Leopolda, Villefranche-sur-mer, France
Photo: richlifestye
This extravagant estate was once owned by King Leopold II of Belgium, who reportedly had it built for one of his many mistresses. It sits on 20-acres of beautiful French countryside which provides stellar views in every direction. It was built from 1929-1931 for an unknown cost, but was valued at $500 million in 2008.