St. Patrick's Day is celebrated on March 17th to honor St. Patrick, the patron saint of Ireland. Key symbols of the holiday include the shamrock, leprechaun, and Celtic cross. Traditional Irish foods like bacon and corned beef are eaten, and music plays an important role in celebrations. Families often wear green and attend church in the morning before celebrating in the afternoon. Major parades are held in various cities around the world, and famous landmarks like the Chicago River and Sydney Opera House are illuminated green in honor of St. Patrick's Day.