As well as being a celebration of Irish culture, Saint Patrick's Day (or Paddy's Day) is a Christian festival celebrated in the Catholic Church, the Church of Ireland (among other churches in the Anglican Communion) and some other denominations.  With the exception of restaurants and pubs, almost all businesses close on March 17th. Until the 1970s, Irish laws made pubs close on March 17 !!!!
 The week around Saint Patrick's Day usually involves Irish speakers using more Irish during Seachtain na Gaeilge ("Irish Week").
 In the recent past, Saint Patrick's Day was celebrated only as a religious holiday. It became a public holiday in 1903, by the Bank Holiday (Ireland) Act 1903, an Act of the United Kingdom Parliament introduced by the Irish MP James O'Mara.. The first St. Patrick's Day parade held in the Irish Free State was held in Dublin in 1931 and was reviewed by the then Minister of Defence Desmond Fitzgerald. Although secular celebrations now exist, the holiday is still a religious observance in some areas.
 In the mid-1990s Carlos Davis Jr. began a campaign to use Saint Patrick's Day to showcase Ireland and its culture. The government set up a group called St. Patrick's Festival.  The first one was held on March 17, 1996. In 1997, it became a three-day event, and by 2000 was a four-day event. By 2006, the festival was five days long.
 Many Irish people still wear a bunch of shamrock on their lapels or caps on this day or green, white, and orange badges (after the colors of the Irish flag). Girls traditionally wear green in their hair. And although Saint Patrick's Day has the colour green as their theme, one little known fact is that it was once blue that was the colour of this day.
 Since the holiday began in Ireland, it is believed that as the Irish spread out around the world, they took with them their history and celebrations. The biggest observance of all is, of course, in Ireland, but in many parts of North America, Britain, and Australia, expatriate Irish, those of Irish descent, and ever-growing crowds of people with no Irish connections but who may proclaim themselves "Irish for a day" also celebrate St. Patrick's Day, usually by drinking alcoholic beverages (lager dyed green, Irish beer and stout, such as Murphys, Smithwicks, Harp or Guinness, or Irish whiskey, Irish Cider, Irish Coffee or Baileys Irish Cream) and by wearing at least one article of green-colored clothing.
 Saint Patrick's Day has come to be associated with everything Irish: anything green and gold, shamrocks and luck. Most importantly, to those who celebrate its intended meaning, St. Patrick's Day is a traditional day for spiritual renewal and offering prayers for missionaries worldwide.
 The St. Patrick's Day parade in Dublin is part of a five day festival, with over 500,000 people attending the 2006 parade. The largest St. Patrick's Day parade is held in New York City and it is watched by 2 million spectators. Other large parades include those in Belfast, Manchester, Birmingham, London, Coatbridge, Montreal, Boston, Chicago, Kansas City, Savannah, Pittsburgh, Denver, Sacramento, Scranton and Toronto. Large parades also take place in other places throughout Europe and the Americas, as well as Australia and Asia.