NATO stands for North Atlantic Treaty Organisation and was formed by the signing of the treaty of the same name in Washington in 1949. The video above which has been put together by NATO gives you a fascinating glimpse into the hopes and aims that went into forming the alliance 65 years ago.
Those aims were to keep the peace in post-war Europe by binding the continent's countries together and preventing any return to 'militarism' by any European powers. It would do that by ensuring a strong American presence.
In practice that came to mean trying to hold back the Soviet Union and to stop the spread of communism. Russia and its allies responded by forming the Warsaw Pact and the long decades of the Cold War began.
So when the Berlin Wall fell in 1989 and the Cold War ended, many questioned NATO's purpose.
Uncertainty in the former communist countries and a peacekeeping role in Kosovo and Bosnia seemed to answer that question. Dr Christian Bueger, Reader in International Relations at Cardiff University, says that NATO changed during that period.
Nato has been changing a lot since the 1990s. Of course it was created to deter the Soviet Union and to ensure the Cold war doesn't turn hot. Since the 1990s, NATO has become an organisation that is a lot more about values - human rights, democracy and so on. In the 1990s, NATO was all about promoting those values. This has changed with the Kosovo crisis fundamentally because NATO now is also an organisation that runs peace operations and stabilisation operations
NATO has continued growing. There are now 28 members. Former communist countries like Poland, Croatia and the Czech Republic have joined longer-standing allies like the UK, the US and France.
But the organisation's central aim remains the same:
NATO's essential purpose is to safeguard the freedom and security of its members through political and military means
It's the famous Article 5 of the North Atlantic Treaty which sets out the principle that an attack on one or more members is considered as an attack on all.
NATO is committed to the principle that an attack against one or several members is considered as an attack against all. This is the principle of collective defence, which is enshrined in Article 5 of the Washington Treaty.
In its sixty-five year history, Article 5 has only been invoked once. That was by the United States in response to the September the 11th attacks. NATO helped but didn't lead the action in Afghanistan which followed.
The leaders of the 28 member countries, their senior ministers and officials are about to descend on the Celtic Manor Resort in Newport for the 2014 Summit along with thousands of journalists and security forces.
The summits take place every two years but a lot of the real negotiation takes place behind the scenes of course. I asked someone who's had personal experience of previous summits, the former Foreign Office minister, Kim Howells, whether they're worth the effort.
Usually the Sherpas as they call the diplomats and the lesser-known military commanders - they'll have already discussed these big issues like Ukraine and Russia, like the Middle East, like North Africa. And if they've done their work properly then the big guys arrive: the presidents and the prime ministers and so on and they'll be there ostensibly to cross the Ts and dot the Is and sign the agreements. So work does get done but very often it gets done before the NATO summit rather than during the NATO summit.
And his experience is backed up by Dr Christian Bueger, from Cardiff University.
Well a lot of it is of course scripted in advance. The major decisions will have been made prior to the summit. But think of it like a family meeting. What happens at a family meeting? You meet face to face - you can talk about disagreements and you can find compromise and it's also good if the heads of state are meeting in person. So this what you need a summit for.
It won't necessarily be a happy family meeting - either inside or out. The summits attract protestors who see NATO as part of the problem not the solution. Sometimes - as was seen in Chicago two years ago - those protests spill over into skirmishes.
That's why the security measures are so tight at Newport and the sites which will be used in Cardiff. Security and defence: it's what NATO's all about