A guy named Mark Dice (who describes himself as "an expert on secret societies, conspiracies, and government cover-ups") runs a YouTube channel where he goes out on the street and asks easy questions to show how ignorant people are. He went to a beach in San Diego for the Fourth of July and asked people why we celebrate it, and some of the answers he received were pretty terrible.

One woman he talked to thought the Declaration of Independence was signed in 1964.  Then she realized she was wrong and changed her answer to 1984.  And that's not even the worst of the answers.