It and its ancillary festivities constitute Super Bowl Sunday and has become likened to a de facto U.S. national holiday .
Super Bowl Sunday over the years has become the most - watched U.S. television broadcast of the year .
It and its ancillary festivities constitute Super Bowl Sunday , which over the years has become the most - watched U.S. television broadcast of the year , and has become likened to a de facto U.S. national holiday .