The Chicago River has been dyed a bright shade of green, kicking off the city's St. Patrick's Day festivities on Saturday. /VCG Photo

Thousands of people lined the riverfront in downtown Chicago to see the dyeing, a holiday tradition that dates back to 1962. /VCG Photo

St. Patrick’s Day is held in observance of the death of St. Patrick, the patron saint of Ireland. It has evolved into a variety of festivals across the globe celebrating Irish culture with parades, foods, dancing and a lot of green. /VCG Photo

A man joins St. Patrick's Day celebration with dyed green hair and green accessories. /VCG Photo