Regardless of American intent, some foreign states played by the rules by day and gathered information by night. In an effort to promote stability after the War, the United Nations was created and headquartered in New York City. Federal agencies had their hands full curbing the relentless influx of spies onto U.S. Distrust and resentment continued to fester between the two superpowers in the wake of World War II. The finest agents this side of the Berlin Wall were pitted against KGB spies determined to steal our secrets. During the darkest years of the Cold War, the United States and the Soviet Union played a nuclear game of cat and mouse.