00:00 St. Patrick's Day is celebrated worldwide, but many people don't know who St. Patrick was or why we celebrate his day.

01:51 Saint Patrick, the patron saint of Ireland, almost certainly existed and was born in the late fourth century in Roman Britain, and his feast day is now a celebration of Ireland itself.

03:11 Saint Patrick escaped from captivity, returned to his family, became a priest, and was eventually sent to Ireland to convert the pagans, where he established missions, organizations, and baptized thousands of people, but faced resistance from tribal rulers; he also used the shamrock to explain the trinity and supposedly drove all the snakes out of Ireland.

04:19 Saint Patrick's Day was originally just a religious feast day in Ireland, but most of the modern traditions associated with the holiday actually came from the Irish diaspora in the United States, with the first recorded parade taking place in Florida in 1601.

05:39 The rise in popularity of Saint Patrick's Day festivities in the mid 19th century coincided with the surge in Irish immigration to America due to the Irish potato famine, and the celebrations were a way for Irish people to fight back against anti-Irish sentiment in America.

06:59 The city of Chicago started dying the Chicago River green on St. Patrick's Day in 1962, a tradition that began with sewage workers using dye to find leaks.

08:11 In Ireland, Saint Patrick's Day is now a three-day festival and the Irish government uses it as a way to export Irish culture, despite the fact that the celebration is named after a British saint and many of the traditions originated in America.