Leaders and nations

It led the Western bloc against the Soviet Union, founding and heading NATO (1949) and defending Western Europe.

Economic strength, a nuclear arsenal, and leadership of the Western/NATO bloc.

The US policy of stopping communism from spreading, without attacking it where it already ruled. Truman's master strategy from 1947.

Truman's promise of US aid and support to any free country resisting communism, starting with Greece and Turkey.

About $13 billion of US aid to rebuild Western Europe, so a prosperous Europe would resist communism — containment through economics.

He ordered the Berlin Airlift, flying in food and fuel for nearly a year instead of fighting, and won the crisis without a shot.

To contain communism after North Korea invaded the South — containment turned into actual fighting under a UN flag.

Having many kinds of force, so the USA could react in proportion to a threat instead of choosing between doing nothing and nuclear war.

He imposed a naval blockade and negotiated the Soviet missiles out of Cuba, avoiding invasion or nuclear war.

Reagan's plan for a space-based shield to destroy Soviet missiles. It frightened Moscow, which feared it could never afford to match it.

He began with renewed confrontation and a military build-up, then negotiated with Gorbachev, signing the INF Treaty in 1987.

The belief that if one country fell to communism, its neighbours would topple too — used to justify defending Korea and Vietnam.

Keeping such powerful nuclear forces that the enemy dare not attack, for fear of being destroyed in return.

A large command economy, a massive nuclear arsenal, and leadership of the Eastern bloc (Warsaw Pact).

An economy where the state, not the market, decides what is produced and owns industry.

For security — a ring of friendly communist states to protect the USSR from invasion after the trauma of WWII.

Stalin cut off land routes to West Berlin to force the West out; it was defeated by the Berlin Airlift — a key Cold War origin.

'Peaceful coexistence' with the West and de-Stalinization (criticising Stalin's crimes).

Crushing the Hungarian Uprising (1956), the Berlin Crisis and Wall (1961), and the Cuban Missile Crisis (1962).

'Limited sovereignty' — the USSR's claimed right to intervene by force in any socialist state straying from communism.

Glasnost = openness; perestroika = restructuring — Gorbachev's reforms to save the failing Soviet system.

A foreign policy of cooperation with the West that abandoned using force to hold the bloc, easing military costs.

A stagnant economy and the costs of the arms race, the bloc and Afghanistan forced retreat: arms deals, dropping the Brezhnev Doctrine, and leaving Afghanistan.

Gorbachev abandoned the Brezhnev Doctrine and refused to send tanks, so unsupported communist governments fell.

Stalin built and forcibly held the buffer zone; Gorbachev, facing economic collapse, chose to release it and end the Cold War.

A world dominated by two rival superpowers, the USA and the USSR, each leading its own bloc with its own alliance and economic system.

The North Atlantic Treaty Organization — the Western military alliance led by the USA, formed in 1949 to defend Western Europe.

The Soviet military alliance of Eastern European communist states, set up in 1955 to bind them to Moscow.

Capitalism: private owners run business for profit. Communism: the state owns the economy and aims for equality.

A region a great power controls or heavily shapes. The USSR controlled Eastern Europe; the USA influenced Western Europe and beyond.

The imaginary barrier splitting communist Eastern Europe from the capitalist West, named by Churchill in a famous 1946 speech.

Each side believed its system was best and the other was dangerous, making the rivalry feel like good against evil and hard to compromise.

The 1957 launch of Sputnik, the first satellite, suggested communism could out-invent capitalism and shocked the USA.

A conflict where rival powers back opposing sides instead of fighting directly — such as Korea, Vietnam and Afghanistan.

The 13-day nuclear standoff was the closest brush with war; the fear it caused pushed both sides towards détente in the 1970s.

A deliberate easing of tension between the superpowers, mainly in the 1970s, including summits and arms-control deals like SALT.

Their personalities and choices raised or lowered tension — Stalin tightened control, while Gorbachev's openness helped end the Cold War peacefully.