Patriots’ Day is sometimes called Patriot’s Day, and this is celebrated to commemorate the battles of Lexington and Concord. These are battles that show that the American ancestors at that time we're already thinking of ways to be free. Some people may become confused with this and Patriot Day, which is usually celebrated to remember the terrorist attack that happened last September 11, 2001.
This is also known as the 9/11 terrorist attack. This is meant to commemorate all of the brave individuals who sacrificed their lives for other people. There were a lot of victims of this attack, and some of the victims have never been found anymore.