NBC celebrates the nation's 237th birthday with a live broadcast of the "Macy's 4th of July Fireworks Spectacular," featuring all-star performances by multi-platinum singer-songwriter Mariah Carey, GRAMMY® Award winning Tim McGraw and others. Hosted by Nick Cannon of NBC's "America's Got Talent," the two-hour show will air on Thursday, July 4th from 8-10 p.m. ET, with an encore presentation of the second hour of the fireworks special airing at 10 p.m.