In the century prior to the UN's creation, several international treaty organizations and conferences had been formed to regulate conflicts between nations, such as the International Committee of the Red Cross and the Hague Conventions of 1899 and 1907. Following the catastrophic loss of life in World War I, the Paris Peace Conference established the League of Nations to maintain harmony between the nations. This organization successfully resolved some territorial disputes and created international structures for areas such as postal mail, aviation, and opium control, some of which would later be absorbed into the UN. However, the League lacked representation for colonial peoples (then half the world's population) and significant participation from several major powers, including the US, USSR, Germany, and Japan; it failed to act against the 1931 Japanese invasion of Manchuria, the Second Italo-Ethiopian War in 1935, the 1937 Japanese occupation of China, and Nazi expansions under Adolf Hitler that escalated into World War II.