St. Patrick's Day falls on March 17 every year — a celebration of Ireland's patron saint that has grown into a worldwide festival of all things green. This countdown ticks to the next one.
Patrick wasn't actually Irish — he was born in Roman Britain, kidnapped to Ireland as a teenager, and returned later as a missionary. March 17 marks the traditional date of his death around 461 AD, and the shamrock legend comes from his teaching.
New York has held a St. Patrick's Day parade since 1762, Chicago dyes its river green, and cities from Dublin to Tokyo throw festivals. In Ireland it's both a national holiday and, historically, a religious feast day.