What caused the mass popular movements in European countries in the late 1960s?

Mass popular movements in European countries during this period were associated with the fact that the global political situation was beginning to change. If before that the USSR and the United States maintained clear positions in Europe, then after the death of Stalin and the strengthening of European countries, people increasingly began to express dissatisfaction with the current situation. As a result, numerous social movements emerged that called for freedom of speech, respect for human rights and support for the right of peoples to self-determination.