1951: The United States was involved in the Korean Conflict to help keep communist North Korea out of South Korea. Fighting ended in a truce in 1953 that established a De-Militarized Zone, but tensions between the two counties continue to this day.

1964-1973: U.S. troops were active in combat in South Vietnam, in an attempt to keep Communist-backed North Vietnam from overtaking the country. In 1973 the U.S. withdrew military support, and South Vietnam was conquered in 1975.

1990: Straining under the weight of an unproductive economy, the Soviet Union, the world's largest Communist country, dissolved.

Today: Communism is not considered a threat to America, with the most stable Communist countries existing being tiny Cuba and isolationist China.

1951: The first nuclear fusion reactor for providing power was built by the U.S. Atomic Energy Commission.

1979: An accident at the Three Mile Island nuclear plant near Harrisburg, Pennsylvania...