Social inequality is something that is fundamental to society and a fundamental part of sociology as a whole. Inequality that exists within a society, whether through money, prestige, power or ascribed status, is present in all societies and is known as social stratification. Social stratification ties together nearly every aspect of society and helps understand a wide range of other changes that occur within a society. For this reason it is important to understand the social stratifications that exist in societies and the various differences present in each type of stratification. These various forms include the slavery system, the caste system and the class system. Slavery is the most extreme form of inequality that exists within the world.