Hello to all my readers! I want to wish you all a happy St. Patrick's Day today!
This day is about Saint Patrick, the patron saint of Ireland. The day celebrates Christianity coming to Ireland (which St. Patrick was credited for), and has also become a celebration of Irish culture in general. Basically, St. Patrick used the shamrock to explain the concept of the Holy Trinity to people there, which is why the shamrock is used as a symbol of this day.
In Ireland, the day is a public holiday. It's celebrated in other countries with Irish populations as well, mainly in the form of parades and wearing green. You can read more about the day here, and you can read more about the man himself here.
Have a happy day, and don't forget to wear something green!