Which major organization was established after World War II to promote international cooperation?

The establishment of the United Nations after World War II marked a significant effort to foster international cooperation and prevent future conflicts. Created in 1945, the UN aimed to bring together countries to discuss issues of common concern and to promote peace, security, and human rights across the globe. It serves as a forum for dialogue, a platform for negotiation, and a means to coordinate international responses to global challenges. The organization's principles are rooted in the collective desire to avoid the catastrophic consequences of another world war, which were starkly illustrated during World War II.

The other organizations mentioned, although important in their contexts, do not fit the criteria of being established specifically to promote international cooperation in the same broad manner as the United Nations. The League of Nations was created after World War I but ultimately failed to maintain peace. The North Atlantic Treaty Organization (NATO) was formed primarily for military defense among member countries during the Cold War. The European Union emerged from the intention of fostering economic cooperation in Europe but addresses cooperation largely within that regional scope rather than on a global scale.