Why is the United States the most powerful country today? social, economic, political and cultural causes

We take it for granted that the United States is the most powerful country on Earth today, and perhaps in human history. The story of how that came to be is long, fascinating, complex — and often misunderstood. Here, excerpted in part from "70 maps that explain America," are maps that help show some of the key moments and forces that contributed to the US's rise as sole global superpower.