Mayo's Thomas Flatley emigrated to the US in 1950 with just $32 in his pocket. More than the next four decades he built up $1.2bn real estate empire - focused largely on the Boston area.
He also owned New Hampshire television station WNHT. The staunchly Catholic businessman died in 2008, and his family are giving away much of the fortune to good causes. The Flatley Foundation had €511m in assets at the end of 2014.