This document provides an overview of the historical development of international organizations aimed at promoting peace, including Kant's vision of perpetual peace in 1795, the Concert of Europe in 1814-15, and the Geneva Convention of 1864. It then discusses the establishment and structure of the League of Nations in 1919-1920 after World War I, its goals of preventing war and collective security, and its ultimate failures. Finally, it outlines the rise of the UN after World War II and its expanded structure and role compared to the League of Nations.