Seventy years ago the world first witnessed the devastating power of nuclear weapons as atom bombs were dropped on the Japanese cities of Hiroshima and Nagasaki. Fear of a repeat dominated the subsequent Cold War.
There were alarmist information campaigns and mass protests calling for nuclear disarmament, but that did not stop a significant proliferation of nuclear weapons, and the US drawing up the ‘star wars’ programme to defend itself from space.
6 August 1945
On 6 August 1945 the first atomic bomb was dropped on the Japanese city of Hiroshima with devastating results.
The blast destroyed more than six square miles of the city. It was estimated that up 140,000 people died as a result. On 9 August, a second atomic bomb was dropped on Nagasaki, killing at least 50,000 people. The morality of the bombings has been the subject of intense debate with some arguing that such an attack was indefensible while others maintain that it saved lives by bringing the war to a quicker end.The tram that survived the Hiroshima bombWhen time stood still: A Hiroshima survivor's story
Tests of strength
A sense of mistrust between the Soviet Union and the West (primarily the US and UK) led to a nuclear arms race in the wake of World War Two.
Britain became the third country, after the US and the Soviet Union, to test an atomic device, in 1952. The development of nuclear arms continued when America detonated the first Hydrogen bomb later that year. Hydrogen bombs were up to 1,000 times more powerful than the atomic bombs used during World War Two. The testing site at Bikini Atoll in the Pacific Ocean has become a UNESCO World Heritage site as an example of the consequences of Nuclear tests.The impact of British nuclear tests in AustraliaBritain's struggles in the nuclear race
The Cuban Missile Crisis
Cold War tensions reached their peak during the Cuban Missile Crisis in October 1962.
The discovery of Soviet missiles in Cuba by U-2 reconnaissance planes led US President John F Kennedy to establish a naval blockade, preventing further missiles entering Cuba (a mere 90 miles from US land). Kennedy also demanded the removal of existing missiles from the island. As confrontation loomed, Soviet leader Nikita Khrushchev ordered all ships to return to the Soviet Union. For 14 days the world had stood on the precipice of nuclear war but a compromise was reached to prevent disaster.Witness: Cuban Missile CrisisCuban missile crisis: The other, secret one
1976 to 1980
Protect and survive
The government's Protect and Survive public information films aimed to tell the public how to survive a nuclear attack.
The 20 short instructional films were only intended for broadcast in the event of a nuclear attack but in early 1980, details were leaked to the press. The information provoked anxiety in some, while others ridiculed the advice, which included shutting curtains as a means of protection from a nuclear fall-out.Witness: Protect and SurviveThree public information films
1981 to 1982
'No more nukes!'
There has been considerable opposition to nuclear weapons ever since the first atom bombs were dropped on Hiroshima and Nagasaki in 1945.
The anti-nuclear movement received considerable media attention in the early 1980s after two high-profile protests. The Greenham Common Women's Peace Camp protested against the announcement that cruise missiles were to be stored at the the American airbase in Berkshire. On June 12, 1982 approximately one million people gathered in New York’s Central Park to protest against nuclear weaponry. It was, at the time, the biggest protest in US political history.Greenham Common nuclear weapon protests anniversaryAnti-Trident 'peace scarf' protest by CND
Ronald Reagan unveiled the Strategic Defense Initiative (SDI) in 1983 which aimed to use lasers to protect the US against the threat of nuclear war.
Reagan wanted to create a defensive shield in space, using laser technology to destroy incoming hostile nuclear missiles. Some claimed it contravened a Soviet-American agreement which prohibited development of anti-ballistic missile systems. The project was never realised.BBC Bitesize: The USA and the USSRReagan's Russian broadcast
1990s to present day
The second nuclear age
After the Cold War ended the threat of nuclear war between the US and Russia subsided but the proliferation of nuclear weaponry continued apace.
The Treaty on the Non-Proliferation of Nuclear Weapons came into effect in 1970, permitting only the US, Russia, the UK, France and China to have nuclear weapons. In recent years, however, Israel, India and Pakistan are thought to have amassed nuclear weapons while Iran and North Korea are also suspected of having nuclear ambitions. North Korea has carried out nuclear tests but whether the country has the the means to deliver its nuclear capability remains unknown.Which countries have nuclear weapons?Is there a new nuclear arms race?