Although apartheid simply means apartness and has been practiced by a number of countries, including the US via racial segregation, it is usually identified with South Africa. Under apartheid, blacks in South Africa were legally second-class citizens who were persecuted, denied access to power, and forced to live in poorer, separate neighborhoods that lacked decent infrastructure or amenities.
Apartheid was largely condemned on the world stage for its injustice. It impacted world history in its collapse, which was due to both persistent internal resistance in South Africa and to external pressure through boycotts and protests carried out by countries such as the United States and Britain. The protest against apartheid also popularized the idea of divestment or withdrawing institutional funding and support for business ventures in an offending country. Many universities in the US were pressured by students into divesting.
South Africa showed the world that moral pressure could be used to help collapse an immoral system. After the fall of apartheid, South Africa's president Nelson Mandela also influenced history, especially in other African countries, through reconciliation committees, which offered forgiveness to offenders in return for them honestly admitting to their crimes. The idea was to heal, not punish. While controversial, the idea of reconciliation did make an impact on the world stage.