Nato - the North Atlantic Treaty Organization - was formed in 1949 by 12 countries, including the US, UK, Canada and France.
Its aim was to block expansion by the then Soviet Union - a group of states which included Russia.
The UK’s foreign secretary at the time, Ernest Bevin, played a key role in persuading the US to join the alliance.
This programme, produced and presented by Vicky Farncombe, tells the story of Nato's founding using archive interviews.
(Credit: Ernest Bevin signs the North Atlantic treaty. Credit: Getty Images)