Monday, March 17, is the holiday to celebrate everything Irish, including St. Patrick, the patron saint of Ireland. Cities across the U.S. will celebrate with parades of green adornment, Irish foods and thematic bar crawls.

It was a sea of green and gold in St. Paul on Monday as thousands gathered to celebrate the city's annual St. Patrick's Day parade. "It's beautiful to see everyone wearing green — no matter what your nationality or where you're from," Dan Kelly said.

As many people find green to wear today and head to a local pub for a green beer, the meaning behind St. Patrick’s Day goes beyond color and pinching. Here are some facts to know about the Irish holiday.