The UN began after WWII in order for collective security (like the League of Nations but it worked). The UN has been involved in the following parts of history: the 1941 Atlantic Charter, Dumbarton Oaks Conference in Washington DC, Yalta, General Assembly, Korean War first altercation that the UN intervened in. They are made up of the following: Security Council, The Secretariat, International Court of Justice. They contribute to Humanitarian Agencies of the UN that deal with the following: Food and Agricultural Organization (FAO), World Health Organization (WHO) -helps with HIV and Swine Flu victims, International Labour Organization (ILO) - not that successful, countries want to deal with their own labour, International Monetary Fund (IMF) - very prominent, helped countries with bankruptcy, UNESCO - protection of heritage sites around the world and UNICEF - helping children after disasters (natural, wartime, child soldiers). In my opinion, the UN has been successful when it comes to UNICEF and WHO, and behind the scenes the IMF. For the mandates that were made in 1945, they were attempts to meet that mandate, but as the world is developing, there have been other priorities.
In 1900, only one of the worlds countries permitted women the right to vote; however 74 years later, 129 countries had permitted this right for women. However, women were not treated equally in the work force which is an ongoing conflict to this day. Figureheads such as Margaret Thatcher, the first woman elected head of state in Europe and Indira Gandhi, the first Female president in India helped equalize women's rights as their influence was not ignored. By the late 1960's almost all women had access to birth control. This meant that women could have a say in when they wanted to have children, therefore allowing them to pursue their careers and further bring them closer in equality to men. They gained the right of choice. After gaining the right to vote, the issue of equal pay arose and because women still didn't receive the same level of pay as men did, the solution resulted in more women entering into politics. After the elimination of slavery in the 1960's, "coloured" people remained to be treated differently throughout the 20th century. Schools, transportation, restaurants and even public spaces such as beaches were segregated, ghettos were formed in the northern cities and groups harassed and murdered black citizens. This era of segregation separated blacks from whites socially, politically, and economically consequently, beating down a race. In 1954, the Supreme Court ruled to desegregate schools and later parks, public housing, air terminals, buses etc. I don't think that these movements really "fizzled out" because women still have the right to vote, equal pay, and right to choice. For the African Americans, there may be areas in the US that are still pretty racist towards them, but overall they are pretty equal.
The all-white National Party came to power in 1948 in South Africa who separated non-whites from whites in many different ways, called the Apartheid. Non-whites could not choose where they wanted to live, marry outside of their race, or travel. These rules were enforced by the army and police forces across the country. The similarities between Apartheid and India trying to get their independence was that both countries had leaders such as Nelson Mandela and Mohandas Gandhi that would be leaders in the resistance. However, Nelson Mandela would use violence, such as the Sharpville Massacre or the Soweto Massacre. Gandhi lead his protest, believing in non-violence such as the Salt March. India finally gained their independence after the partition, leading to dividing the country with Pakistan.