In this day and age people say things that aren't necessarily true. It isn't because they're lying, it's because some of the things that are “common knowledge” are simply wrong. Here are a few about the United States.
The United States is a democracy
This is a common misconception that is bandied about. The United States is technically a constitutional republic. Now, that doesn't really mean anything to the majority of the people, but it is critically important. What it means is that the People have a voice in what happens, but the Constitution is what rules unless the Constitution is changed. In practice it keeps the majority from tyranny over the minority. So, just because a majority of people are for or against something doesn't mean that it is allowed.
Benjamin Franklin was a President
Again, this is a common misconception fueled mostly by Mr. Franklin's face on the hundred dollar bill. Mr. Franklin was a scholar, an inventor and one of the great Fathers of the United States, but he was never President.
The national motto is “E Pluribus Unum”
The official motto of the United States is “In God We Trust”. This is controversial, but it was signed into law by President Eisenhower in 1956. It is interesting to note that the phrase, “under God” was added to the Pledge of Allegiance in 1954. The other motto of the United States, E Pluribus Unum (out of many, one), is more acceptable to some people, but is not the official national motto.
The first shot of the Civil War was at Ft. Sumter
While it's true that the first shot of the Civil War was fired by South Carolinians it was not fired at Ft. Sumter. Instead it was fired at the vessel the “Star of the West” which was taking supplies to Maj. Anderson at Ft. Sumter. Citadel cadets (from The Citadel, a military school in Charleston, S.C.) under the command of Maj. Stephens fired on the “Star of the West” from a battery placed on Morris Island fronting Charleston harbor.
The Wright Brothers invented powered flight
This is a very sticky subject among aviation historians that seems to be centered on what constitutes a powered, controlled flight. Certainly, the Wright Brothers deserve an enormous amount of credit, but powered flight was achieved by several people in several countries before and immediately after the Wrights. Americans take a great deal of pride in having “invented” the airplane, but it's more likely that Americans invented the exploitation of the airplane, rather than the aircraft itself.