Lily Safra (estimated worth $1.2 billion)
King Leopold II of Belgium (1853-1909) was a player. He allegedly built many waterside homes for his numerous girlfriends. While this property was his,Villa La Leopolda in its current incarnation was designed and built from 1929 to 1931 by an American architect, Ogden Codman, Jr.and is valued at 500 million. The estate hit the block in 2008 and a Russian billionaire named Mikhail Prokhorov threw his hat in the ring and made a bid to buy the famed love shack (20 acres is more than a love shack). After the world economic crisis dove into full swing, he pulled out and lost his paltry 50 million euro deposit. Bummer town.