It's St. Patrick's Day and millions will celebrate the day by drinking green beer and wearing something green. So why are we celebrating St. Patrick's Day? Most probably couldn't say. In fact, most people don't even know who St. Patrick was. National Geographic has you covered though with a great read on the myths, facts, and tradition's of St. Patrick's Day. Here are a few examples:

For starters, the real St. Patrick wasn't even Irish. He was born in Britain around A.D. 390 to an aristocratic Christian family with a townhouse, a country villa, and plenty of slaves.

What's more, Patrick professed no interest in Christianity as a young boy, Freeman noted.

At 16, Patrick's world turned: He was kidnapped and sent overseas to tend sheep as a slave in the chilly, mountainous countryside of Ireland for seven years. (See Ireland pictures. )

"It was just horrible for him," Freeman said. "But he got a religious conversion while he was there and became a very deeply believing Christian."

and...

According to St. Patrick's Day lore, Patrick used the three leaves of a shamrock to explain the Christian holy trinity: the Father, the Son, and the Holy Spirit.

Today, St. Patrick's Day revelers wear a shamrock. Trifolium dubium, the wild-growing, three-leaf clover that some botanists consider the official shamrock, is an annual plant that germinates in the spring.

Until the 1970s, St. Patrick's Day in Ireland was a minor religious holiday. A priest would acknowledge the feast day, and families would celebrate with a big meal, but that was about it.

"St. Patrick's Day was basically invented in America by Irish-Americans," Freeman said.

And of course, the beer:

On any given day 5.5 million pints of Guinness, the famous Irish stout brand, are consumed around the world.

But on St. Patrick's Day, that number more than doubles to 13 million pints, said Beth Davies Ryan, global corporate-relations director of Guinness.

"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," she said.

You can read more by going to the link above. Have a happy and safe St. Patrick's Day!