Nato leaders gathered in Newport, Wales, on Thursday, for the start of a two-day summit dubbed the group's most important since the Cold War.
Behind over 12 miles of steel fencing, leaders plan to discuss Isis' advance across Iraq and Syria; the crisis in Ukraine and the nation's bid to join Nato; as well as the group's military mission in Afghanistan.
Issues including threats to national security in Nato countries, including cyber-attacks and terrorism, will also be up for discussion.
But what is Nato, and what is its role in the current global crisis?
What is Nato?
Its name, which stands for the North Atlantic Treaty Organization, was founded in 1949 - two years after the beginning of the Cold War - and is backed by the nuclear arsenal of the US, UK and France.
At its founding, Lord Ismay, the first NATO Secretary General, famously stated the group’s goal was: “to keep the Russians out, the Americans in, and the Germans down.”
In 2010, Admiral Giampaolo di Paola, the-then chairman of Nato’s military committee, rephrased Lord Ismay’s original statement: “to keep North America in, Europe up, and Russia with”.
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How the Nato group appeared in 1952
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In 1955, the country then known as West Germany joined Nato.
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In the early Eighties, Spain joins Nato.
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A re-unified Germany joins Nato.
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The Czech Republic, Hungary and Poland become the first former Soviet bloc states to join Nato, moving the alliance's borders some 400 miles towards Russia.
Bulgaria, Estonia, Lithuania, Latvia, Romania, Slovakia and Slovenia are made new members.
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At Nato's 60th anniversary summit, Albania and Croatia are formally inducted into group - increasing its membership to 28.
Who is a member?
The North Atlantic countries which founded the group include: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom and the United States.
Over a course of decades, these nations were joined by: Greece, Turkey, Germany and Spain, and later, former communist nations including: the Czech Republic, Hungary, Poland, Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, Slovenia, Albania and Croatia.
However, Finland did not join its Scandinavian neighbours Sweden and Norway in the Nato alliance. After the 1917 Russian revolution, it won independence from Moscow but almost lost it again fighting the Soviet Union in WWII.
The country has therefore adopted a policy of staying economically close with the West while avoiding confronting Russia.
What will be discussed at the summit in Wales?
As the crisis in Iraq and Syria shows no sign of easing following the beheading of US journalist Steven Sotloff, and the threat that a British aid worker may be next, the summit’s programme was hastily revised to include how Nato can bolster its existing operations in the region. Equipping Kurdish forces, sending humanitarian aid to besieged communities and intelligence and surveillance assistance will be on the agenda.
Ukraine joining other former Soviet Union nations in Nato will also be discussed – a particularly tense topic in light of escalating Russian military intervention in the east of Ukraine.
On Thursday, Russia’s Foreign minister Sergey Lavrov called Kiev’s ambitions to join Nato a “blatant attempt to derail” ceasefire talks in eastern Ukraine.
Undeterred, Ukraine’s President Petro Poroshenko went ahead with a meeting with top Nato leaders.