The general wisdom is that the 1960s were the most radical decade in terms of political upheaval in the post-war period. It is often contrasted with the allegedly conservative 1950s. This view is put forth by a lot of former 1960s radicals like Todd Gitlin, Mark Kurlansky and David Horowitz. But, from an international viewpoint it appears that the 1950s were far from conservative and were in many ways more radical than the following decade. Further much of what was considered radical in the 1960s only occurred because it built upon a foundation developed in the 1950s.
The most important development in the world after the end of World War II was undoubtedly decolonization. This process really reached the tipping point in the 1950s with the 1960s being mostly follow through. Significant violent revolutionary movements for independence occurred in Indochina, Algeria and Kenya. The 1950s saw the defeat of a significant colonial power, France, militarily by the Vietminh at Dien Bien Phu. In contrast while winning the war, the North Vietnamese never won a single battle against the US during the 1960s. They just wore out our political ability to keep fighting much as the Algerians did to the French in the 1950s. In other areas of the world political revolutions or coups implementing radical policy changes took place in Cuba, Egypt, Iraq, Iran and Guatamala during the 1950s. Far fewer such revolutions took place in the 1960s. The only revolution of the 1960s that comes close to Cuba in terms of radical change was in the politically insignficant nation of South Yemen. The emergence of the Third World which for people outside of Europe and North America represented a radical change from the last century of colonial rule really took place in the 1950s not the 1960s.