The Cold War, roughly 1947 to 1991, gets its name from exactly the fact that makes it unusual among great-power conflicts: the two dominant sides, the United States and the Soviet Union, never engaged each other's armed forces in direct combat. No American and Soviet armies met on a battlefield. Instead, the conflict played out through economic pressure, espionage, an arms race, and — most consequentially — a long series of wars fought by other countries, with both superpowers arming, funding, or directly assisting opposing sides.
Why direct war became unthinkable
Both sides possessed nuclear weapons for nearly the entire Cold War, and by the early 1960s both had enough of them, and reliable enough ways to deliver them, that a full-scale war between the two would have risked mutual destruction on a scale neither side's leadership was willing to gamble. This condition, known as mutually assured destruction, didn't eliminate conflict between the two blocs — it redirected it. Rather than fighting directly, the US and USSR competed for influence in other countries, backed opposing factions in civil wars and independence movements, and built up military capability aimed at deterring the other side from ever crossing the line into direct confrontation.
The wars that weren't "the" war
The redirected conflict showed up as a series of proxy wars across the globe: the Korean War, the Vietnam War, Soviet involvement in Afghanistan, and numerous smaller conflicts in Latin America, Africa, and the Middle East, in which the superpowers rarely committed their own uniformed troops against each other but routinely supplied weapons, funding, advisers, or covert support to opposing local factions. The closest the conflict came to direct war was the 1962 Cuban Missile Crisis, thirteen days in which the discovery of Soviet nuclear missiles in Cuba brought the two superpowers to the brink of direct confrontation before a negotiated withdrawal defused it — widely regarded by historians as the moment the Cold War came closest to turning hot.
What we're still unsure about
Historians broadly agree on the Cold War's major events but continue to debate how inevitable the conflict actually was, and how much responsibility for its start and its worst escalations belongs to each side — competing schools of interpretation, from "orthodox" accounts emphasising Soviet expansionism to "revisionist" accounts emphasising Western economic and strategic motives, have shifted in influence as archives on both sides have gradually opened. There's also ongoing debate over how close the world actually came to nuclear war at several tense moments beyond the Cuban Missile Crisis, since declassified records have shown some episodes were more dangerous, and some safety margins thinner, than was publicly understood at the time.
This sits inside The Cold War, one of seven topics in Contemporary History, one of seven domains in History, one of seventeen subjects the app can quiz you on.