In the late 30s, you have Stalin's purge, where he goes after political opponents, and it's believed that he killed as many as three million people. These things were so shocking to the planet that they made attempts to prevent them in the future. In 1920, out of the trauma of World War I, the League of Nations was founded. It was an attempt to prevent things like this in the future, for nations to talk to each other and to coordinate so they don't go to war, especially at the scale seen in World War I. But clearly, that was unsuccessful, and we have World War II, where even more people die. After which, the slightly stronger United Nations gets founded, once again, with the charter of fostering dialogue between nations so that we can prevent these types of trauma for the planet. Early on in the newly founded UN agenda was this idea of revisiting the ideas of the Enlightenment, this idea of human rights, and trying to codify them in international law.