10 most expensive things ever.

A postal box holding a $400 million diamond. A $700 million yacht with a T-Rex bone on board. A "mistake" that cost the world $22 trillion. And a substance so rare and so explosive that a single gram would cost $62.5 trillion. This is the countdown of the most expensive things to ever exist — cars, art, homes, diamonds, and one entry that isn't owned by anyone at all. Watch till #1, it will change how you think about "expensive."