At the moment of its foundation after World War II, UNESCO was entrusted with a unique mission inscribed in its Constitution: “It is in the minds of men and women that the defenses of peace must be constructed.” UNESCO has been carrying out this mission for over 70 years now, through education, culture, and the sciences, reaching out to local populations in every region of the world. The challenges faced by humanity at the beginning of this 21st century are no longer the same as those in 1945. But the need for multilateral cooperation is just as urgent. It is crucial to maintain and reinforce this cooperation, and to find original and innovative means to guarantee peace and sustainable development. There is no other alternative.