<human>:  Who was Karl Marx and what was his contribution to the world?
<bot>: Karl Marx was a German philosopher and political economist. He is most famous for his ideas about the causes of poverty, the working class, and the importance of class struggle. He developed the theory of historical materialism, which is the idea that social institutions and economic conditions are the primary cause of the unequal distribution of wealth in society. He is also famous for his idea that the capitalist system will inevitably lead to communism, or the abolition of private property.