American century is a term used to describe the period of time in the twentieth century when the US became the most powerful, influential and wealthy country in the world. This happened as the US recovered from a devastating civil war and began to build an economy and military that was unmatched around the world. The US went from being a small nation to the world's superpower, expanding its economic and political influence around the world. This period of American history was so influential that it was called the "American Century". During this time, the US was able to shape the world and its future in a way that had never been done before.