Entering into the 1950s, the United States of America had a distinct advantage over war-torn Europe. While Germany was heavily sanctioned, England, France, Italy, and several other Old World nations were just coming to terms with the heavy investment needed to rebuild their countries.
As a way to make it easier for the rest of the world to rebuild, the Bretton Woods Agreement was adopted. It was innocuously simple: in an effort to keep the United States of America (USA) from buying everything in sight, the Bretton Woods Agreement kept the USA in check by requiring all foreign currencies be pegged to the US Dollar. Some pegs were strong, some pegs were weak, but at the end of the day they never moved more than 1% in any direction. Like today's problem with the Chinese Yuan, forced to a peg against the dollar, it kept a constant, controlled flow of US dollars out of the country.
