The most expensive apartment in the world.
It's still under construction, but when it's complete, Monaco's Odeon Tower will boast the most expensive home in the world: the Sky Penthouse, costing $400 million. That's nearly twice the current record-holder for the most expensive penthouse, London's One Hyde Park, which sold for $223 million. The penthouse features five levels, each with its own kitchen, and a dance floor on the top level that connects (via water slide) to the infinity pool down on the terrace. Parking is extra at $330,000, more than the average U.S. home sells for.