Stolen: $41 million

The week before Christmas 2004, robbers in Belfast, Northern Ireland, dressed as police officers and entered the homes of two bank managers. Their families were held hostage, and the managers were instructed to go to work as normal the next day.

When the workday ended, the managers let the thieves into the bank, where they stole about 26.5 million British pounds and additional foreign currencies in the biggest bank robbery in Irish history.

The case is still unsolved and so far only one person has been arrested, for money laundering