2 books · Ages 10–18
Hidden History is a 2-book series for ages 10–18 by Kenneth C. Davis. Each book stands alone — start anywhere.
Start anywhere — each book stands alone.
That said, In the Shadow of Liberty: The Hidden History of Slavery, Four Presidents, and Five Black Lives and Strongman: The Rise of Five Dictators and the Fall of Democracy are great first picks.
No particular order needed — browse and pick what catches your eye.