World's Most Expensive Apartment Sold: Monte Carlo Penthouse

We always knew that Monte Carlo was pricey, but the sale of a six-bedroom penthouse in the pint-size European principality, for a record-breaking $312 million, takes the prize as the world's most expensive apartment. If such a figure is still obtainable, how bad can the real estate slump be?

The pad's buyer, says Luxist, is the U.S.-born Greek billionaire Constantine Alexander-Goulandris, who earns his keep as an advisor to the Saudi royal family and various Middle Eastern oil potentates, so we suspect that he didn't have trouble getting a mortgage. Oh, he's also said to be worth a cool $15 billion and is cozy with Russian mogul Roman Abramovich.

Alexander-Goulandris reportedly has other residences in Paris, London, Antibes, New York and Hawaii. So why add another to the collection?