By law, pubs in Ireland were closed on St. Patrick's Day, a national religious holiday, as recently as the 1970s.
According to the U.S. Census Bureau, 34 million United States residents claim Irish ancestry, or nearly ten times the entire population of Ireland today, which stands at 3.9 million. Among U.S. ethnic groups, the number of Irish-Americans in the U.S. is second only to the number of German-Americans.
Since 1820, 4.8 million Irish have legally immigrated to the United States, according to the U.S. Census Bureau. The agency reports that only four countriesGermany, Italy, Mexico, and the United Kingdomhave sent more native-born residents to become naturalized U.S. citizens.
Chicago is famous for dyeing the Chicago River green on St. Patrick's Day. The tradition began in 1962, when a pipe fitters unionwith the permission of the mayorpoured a hundred pounds (45 kilograms) of green vegetable dye into the river. (On the job, the workers often use colored dyes to track illegal sewage dumping.) Today only 40 pounds (18 kilograms) of dye are used, enough to turn the river green for several hours.
According to the Friends of the Chicago River, a local environmental group, more people are likely to view the Chicago River on St. Patrick's Day than on any other day.
Guinness stout, first brewed by Arthur Guinness in Dublin, Ireland, in 1759, has become synonymous with Ireland and Irish bars. According to the company's Web site, 1,883,200,000 (that's 1.9 billion) pints of Guinness are consumed around the world every year.
Robert Louis Stevenson, the 19th-century Scottish author of Kidnapped, Treasure Island, and other novels, brought a store of Guinness with him during a trip to Samoa in the South Pacific, according to the Guinness Web site.
Ireland is about 300 miles (480 kilometers) long and 200 miles (320 kilometers) wide. Those facts, along with other features, led Swedish geographer Ulf Erlingsson to recently conclude that the Atlantic Ocean island is the same one identified by ancient Greek philosopher Plato as Atlantis in his famous dialogues Timaeus and Critias.