The security environment in and around the world has become more complex and threats have multiplied. NATO wants to guarantee security for its citizens in an unstable world. This approach is also a response to the demand by the majority of the NATO citizens, who want more security, stability and a coordinated NATO response to current threats.As a summary of what the NATO is, we will say that its essential and enduring purpose is to safeguard the freedom and security of all its members by political and military means. Collective defence is at the heart of the Alliance and creates a spirit of solidarity and cohesion among its members.NATO strives to secure a lasting peace in Europe, based on common values of individual liberty, democracy, human rights and the rule of law. Since the outbreak of crises and conflicts beyond the borders of NATO member countries can jeopardise this objective, the Alliance also contributes to peace and stability through crisis management operations and partnerships. Essentially, NATO not only helps to defend the territory of its members, but engages where possible and when necessary to project its values further afield, prevent crises, manage crises, stabilise post-conflict situations and support reconstruction.NATO also embodies the transatlantic link by which the security of North America is tied to the security of Europe. It is an intergovernmental organisation which provides a forum where members can consult together on any issues they may choose to raise and make decisions on political and military matters affecting their security. No single member country is forced to rely solely on its national capabilities to meet its essential national security objectives. The resulting sense of shared security among members contributes to stability in the Euro-Atlantic area.NATO's fundamental security tasks are laid down in the Washington Treaty. They are sufficiently general to withstand the test of time and are translated into more detail in strategic concepts.Additionally, NATO has carried out a task, not expressly sought in its origins, which is to contribute to peace among European Allies, and of these with the rest of NATO Allies. In this way, the Alliance has been a prop for the maintenance of peace, not only with Russia and the former block of the Warsaw Pact, but also in Western Europe. And we cannot forget the aspect of political and economic cooperation that the Alliance highlights in its Art. 2.