Background
Self-determination can refer to a number of distinct human rights.  These include the right to equality under the law, the right to a nationality, the right to freely leave and return to your country of origin, the right to freedom from persecution because of race, religion, or gender, and a host of others.  Throughout global history these rights have been violated in a number of ways across the globe.  In many places, these basic rights are still denied to various peoples.

Rigid Social Class System
Many of these rights are denied under rigid social class systems such as ones in place during the European Middle Ages, colonial Latin America, and in India.

European Middle Ages: The social class system in place during the Middle Ages denied the majority of people self determination.  The peasant class, or serfs, at the bottom of the system, were tied to the land.  They lived on manors where they performed agricultural work for their lord.  In times of war, they would be drafted for military service.  In return they were offered protection and were allowed to keep some of what they produced.  Serfs had no say in their government, and very little say in their lives overall.

Colonial Latin America:  A rigid social class system began in Latin America during its colonial period.  However, at the end of colonial rule, this system changed very little.

During the various Latin American independence movements, promises were made by the Creoles to give equality to all who helped against the Spanish.  However, when independence was achieved, little changed in this system other than the Creoles now controlled both the land and the government.

India: The Indian social class system is called the Caste System, and is an important part of Hinduism.  Everyone is born into a specific caste, and has certain rights and duties according to their castes. The lowest on the scale are the Untouchables.  It is believed that to even have the shadow of an Untouchable fall across you is bad luck.  To prevent this, Untouchables were required to walk the streets ringing a small bell.  Untouchables led very hard lives and were shunned by society.  They were forced to do the jobs that other castes felt were unclean, such as street cleaning.  Discrimination against the Untouchables was outlawed in the mid 20th century, yet many still face problems in India today.

Violence
The pursuit of self determination, or the denial of it, has often led to violence.  In these cases people have been killed for reasons such as religious affiliation of ethnic background.  These problems range from the Khmer Rouge in Cambodia in the 1970s, to the present day situation in the Balkans.

Amritsar Massacre: On April 3rd of 1919, British soldiers killed close to 400 unarmed Indian men, women, and children, and wounded 1,100 more.  The site of this massacre was the city of Amritsar in northern India.  People had gathered in the center of town to protest British occupation of their country, and to demand equality.  This was a turning point in British domination of India.  Independence movements became very popular and eventually forced India's independence.

Khmer Rouge:  The Khmer Rouge were a group of communist guerillas, led by Pol Pot, that gained control of Cambodia after the withdrawal of American troops from the Vietnam War.  The initiated a reign of terror, killing over a million people to remove all western influence from the country.  This gross violation of human rights ended when Vietnam invaded and occupied the country in 1979.  In the 1990s, the United Nations negotiated a peace settlement, and began the democratic process in Cambodia.

Balkans: Yugoslavia was created at the end of World War I.  It contained various ethnic and religious groups.  After World War II, this area was dominated by the Soviet Union.  After the fall of communism, the various ethnic and religious groups, including the Orthodox Christian Serbs, the Roman Catholic Croats, the Muslim Albanians, and others, attempted to separate from Yugoslavia and form their own nations. The nations of Croatia, Slovenia, and Bosnia and Herzegovina all gained independence at this time.  

However, this independence came at a price.  War and ethnic violence have occurred throughout this region since the breakup.  In Bosnia and Herzegovina, many non Serbs were either killed or forced out of the country by Serb forces.  This policy was called Ethnic Cleansing.  The Yugoslav army, under the guidance of Yugoslavian President Slobodan Milosevic, fought to keep non-Serbs from breaking away from Yugoslavia. During the 1990s, he used his army to terrorize ethnic Albanians in Kosovo, who were asking for self rule.  The North Atlantic Treaty Organization (NATO) finally put a stop to this violence, and Milosovic has since been arrested and awaits trial for war crimes.

Palestine: In the 1890s, European Jews began to migrate to Palestine, which was then controlled by the British Empire.  This migration was a result of the increasing persecution occurring in Europe.  The migrations increased as World War II approached, when many Jews attempted to escape Hitler and the Nazis.  The Arabs already living in Palestine were unhappy about the increasing number of Jewish settlers, which led to sporadic violence throughout the region. At the end of the second World War, the Jewish population in Palestine declared the creation of the new state of Israel.  All of the neighboring Arab nations immediately declared war, but were defeated, and Israel remained free.  Since the end of the World War II, Israel and the various Arab nations have been involved in numerous conflicts as Arab Palestinians fought for an autonomous state.  Israel has been reluctant to grant any sort of self rule, which is a violation of their right to self determination.  This situation has resulted in many acts of violence committed by both sides.  The tool of the Palestinians has been terrorism, while Israel has used its strong army, and the support of the western nations to fight back.  The Israeli government granted limited self rule to the Palestinians in the 1990s, only to begin restrictions again as terrorist activities ceased to occur.

Apartheid: European settlers have ruled South Africa since the mid 17th century.  While South Africa gained independence from the British Empire in the beginning of the 20th century, the country was still controlled by the white minority.  Black South Africans lived under the policy of apartheid, which severely limited their rights.  Under apartheid, black South Africans could only live in certain areas, were required to use separate trains, beaches, restaurants, and schools, and could not enter into an interracial marriage.  The African National Congress, a group formed in protest of this policy, was eventually outlawed due to their violent tactics.  One of its leaders, Nelson Mandela, was imprisoned for over thirty years for his involvement in anti-apartheid demonstrations.  Apartheid lasted until the early 1990s when white South African President, F. W. de Klerk ended apartheid.  In 1994, Nelson Mandela was elected as South Africa's first black president.  However, many human rights problems still exist in this country, as white South Africans still control most of the economic wealth.