When the billions start piling up, what's a mogul to do?
Sure you could buy a $49 million Aspen mansion with its own sewage treatment plant. But why stop there? We started making a list of the bizarre things millionaires do with their money when we spotted this story on folks dropping millions to buy luxurious doomsday-safe condos built in a Cold War-era missile shaft.
There are also deals on bulletproof gear and, of course, insanely expensive jets to buy. Below, a round-up of some of the quirkiest things that ultra wealthy people have done with their money: