The Cold War was a struggle for world dominance between the former Soviet bloc (led by the Soviet Union) and the free and ostensibly free, "capitalist" or anti-Soviet nations of the world, (led by the United States). Lasting from roughly 1945 until 1991, it was categorized by a lack of open warfare (due to the threat of mutually assured nuclear annihilation) and a heavy use of largely Third World proxy fights launched by one or both of the two powers.
Along with the rise and fall of Nazi Germany (and World War II), the Cold War was probably the most defining historical event of the 20th Century.
Brief Chronology of the Cold War
1945: Allied powers defeat Nazi Germany and Imperial Japan, ending World War II. Soviets and Americans effectively divide Europe between themselves - eastern Europe becomes Soviet satellites, western Europe becomes American allies (both ideologically and militarily). Germany is divided between the two powers.
1948: Soviets seal road access to West Berlin, attempting to use the blockade to gain control of the city. Americans and allies commence massive airlift to supply city via air. Nine months later, Soviets relent and reopen the road. 77 airmen were lost during these flights, due to the high tempo that was required.
1949: Soviets test atomic bomb.
1950: A war erupts in Korea as North Korea invades South Korea. A major war is fought over the next three years between a US-led UN force and North Korea, later bolstered by China. War ends in a stalemate, at essentially the same border as pre-war.
1957: American troops begin to militarily aid South Vietnam in its struggle with North Vietnam, marking the beginning of American involvement in the Vietnam War. Over ensuing years, more and more American force is applied in the country, leading to a massive war. American troops withdraw in 1973 after the Paris Peace Accords, following years of massive public protests at home and incessant guerilla warfare and massive numbers of casualties (including over 58,000 dead). The North invaded South Vietnam in 1975.
1962: Cuba is discovered to be setting up Soviet nuclear missiles. Americans commence blockade of Cuba, the two navies come perilously close to open war before the Soviets relent and agree to remove the missiles.
1968: Border skirmishes mark the end of the Soviet-Chinese alliance, eventually leading to a much more tripolar struggle.
1979: Soviets invade Afghanistan. Americans protest, and soon thereafter start aiding guerilla movements within Afghanistan.
1980s: The United States, supported by United States conservatives and a sympathetic Reagan administration, begins aggressively channelling covert and overt weapons to anti-communist resistance movements in Afghanistan, Angola, Cambodia, Nicaragua and other nations in a policy that comes to be known as the Reagan doctrine. Soviet leader Mikhail Gorbachev ultimately labels these wars "a bleeding wound" and retreats from Afghanistan and other Soviet-aligned nations.
1983: President Ronald Reagan lashes out at Soviet Union, calling it an "evil empire."
1989: Soviets quit controlling satellite states, all of them abandon communist government and free their societies. Sensing weakening of Soviet resolve, Berlin Wall is torn down.
1991: Soviet Union collapses, ending Cold War.