Waving in the wind, a flag may not seem like a code. But hidden in the stripes, stars, suns, moons, and colors of the world's flags are the keys to understanding different countries' shared histories and cherished ideals.

Flags do much more than identify countries and groups of people. In every color, pattern, and design, the citizens and governments of countries announce their allegiances and herald their history. If you know what to look for, a flag can reveal major insights into another country's history and culture.