In 2007, "Carlos Hector Flomenbaum" charmed employees of Antwerp's ABN Amro Bank, becoming a frequent and well-liked customer over a year or so who even brought the employees fine chocolates as gifts from his travels as a diamond trader. He even was granted a special pass to access the vaults over the weekend when the bank was closed. Ooops.
Flomenbaum robbed the bank of $28 million in diamonds and was never seen again. The video above tells the incredible story.