Jody Victor: Where did wearing green clothes, and other uses of green for St. Patrick's Day come from? Sometime in the 19th century, as St. Patrick's Day parades were flourishing, wearing the color green became a show of commitment to Ireland. In 1962 the show of solidarity took a spectacular turn in Chicago when the city decided to dye a portion of the Chicago River green.

The tradition started when parade organizer Steve Bailey, head of a plumbers' union, noticed how a dye used to detect river pollution had stained a colleague's overalls a brilliant green. Why not, Bailey thought, turn the river green on St. Patrick's Day? So began the tradition.

The environmental impact of the dye is minimal compared with sources of pollution such as bacteria from sewage-treatment plants. But a group called the Friends of the Chicago River focuses instead on turning the Chicago River into a well-known habitat full of fish, herons, turtles, and beavers. If the river becomes a wildlife haven, the thinking goes, Chicagoans won't want to dye their river green.

Historically speaking, a lot of Irish immigrants came to the United States and brought with them lots of customs and traditions, one of them being Guinness. On any given day 5.5 million pints of Guinness, the famous Irish stout, are consumed around the world. On St. Patrick's Day, that number more than doubles to 13 million pints, according to global corporate relations of Guinness.

Today, the US tradition of St. Patrick's Day parades, packed pubs, and green silliness (including green beer) has invaded Ireland with full force. The country figured out the popularity of St. Patrick's Day was a good way to boost spring tourism.

Whatever the reasons, St. Patrick's Day has become a well known, and loved holiday in the US as well as Ireland. Hope yours was fun!

Jody Victor