Most Entertaining Book That Helped You Understand a Specific Historical Event/Era?

I normally love narrative non-fiction but find the books that I voraciously consume often make me learn a lot but also feel very depressed (Invisible Child, The Wind Catches You and You Fall, Nothing to Envy).

Are there any deeply researched fiction or non-fiction books that informed and entertained you at the same time about a specific, real moment in time that are not utterly bleak?