Americans began observing the Fourth of July as early as 1777, when the first-ever major celebration in Philadelphia included a parade, a thirteen-shot cannon salute, and fireworks, but Congress didn’t make it official until 1870, when it was part of a bill passed to recognize major state holidays at a federal level—like Independence Day, Christmas and New Year’s Day. The Fourth did not become a paid legal holiday until 1938, as part of a that bill that granted holiday leave to employees of the federal government.