Each year on March 17, a sea of green sweeps up New York's Fifth Avenue in the largest St. Patrick's Day parade in the nation. On the other side of the Atlantic, towns throughout Ireland honor the man who brought Christianity to the Emerald Isle with feasts and festivals. THE HISTORY OF ST. PATRICK'S DAY shows how Irish immigrants in America transformed a religious festival into a celebration of all things Irish, and how St. Patrick's Day became a nationwide phenomenon. A glorious reminder of America's multicultural heritage, St. Patrick's Day is also a uniquely American festival. See parades around the country, from tiny towns to the massive New York assembly, where over 150,000 people march in the company of celebrities, campaigning politicians and bagpipers. Explore the unique heritage of St. Patrick's Day in America with members of the Ancient Order of the Hibernians, who are in charge of New York's festivities, and examine the controversy that has surrounded the parade in recent years. It's a comprehensive look at an ancient tradition that has been transformed in America.