Monday, March 17 is St. Patrick's Day, celebrating all things Irish in the U.S. and around the world. Cities celebrate with parades, bar crawls and more.

Every year thousands of revelers fill the streets in the U.S., Ireland and countries worldwide to celebrate Saint Patrick’s Day, but the real Saint Patrick wasn’t even Irish. NBC News’ Joe Fryer took a deeper look at Saint Patrick’s lasting influence and the history behind the holiday.

Celebrations are in full swing and what better place to celebrate than in Ireland itself? Travelzoo's senior editor Gabe Saglie is in Dublin with a look at one of the world's largest St. Patrick's Day parades.