U.S.-Soviet Tensions Post-WWII
Just about every aspect of society has its rivalries. In computers, both philosophical and operational differences have made Apple and Microsoft each other's biggest competitors. In sports, you'd be hard pressed to find a bigger rivalry with more animosity involved than the New York Yankees and the Boston Red Sox in Major League Baseball.
Geopolitics is no different. Rivalries exist between nations based on political and philosophical differences as well, only the implications for these rivalries turning sour can be far worse. Perhaps no rivalry between different nations had greater implications for the entire world than that between the United States and the Soviet Union in the second half of the 20th century. Separated by vastly different political, economic, and social philosophies, tensions between the Soviet Union and the United States, a period historians term the Cold War, had the potential to lead to the end of the world as we know it.