Er... [How to explain the Revolution to someone with no sense of Earth history or geography?]

You see, the people living in America were really from England, so they were still subjects of the English government. But after a while, there were so many of them, and their lives were so different from the people back at home, that they wanted to form their own country. England didn't want that to happen, but America did it anyway... so every year Americans celebrate that separation.