Nestled atop a 49-story building in Monaco, this multi-level penthouse spans a whopping 33,000 square feet, and includes 6 bedrooms, a water slide from the second balcony taking you right into the infinity pool overlooking the ocean. As of right now the Tour Odeon penthouse is still under construction, and is slated to hit the market in 2014. If everything goes according to plan, this will in fact be the most expensive penthouse ever listed with a projected asking price of more than $250 million. I guess Monaco really is the playground for billionaires after all.