There is more income inequality between countries today than at any point in time in history. For example, the average American has about 80 times as much purchasing power as the average resident of the Central African Republic (i.e. the average American has sufficient income to buy about 80 times more stuff than the average CAR resident, even after we adjust for differences in living costs.) This difference holds when looking at non income-based measures of development such as health and education. For example, life expectancy at birth is about 84 years in Japan and only 54 years in Lesotho. The average Australian has about 13 years of education completed, while the average Afghan has only about 5 years of education completed. Why do you think we observe such large differences in living standards between the richest and poorest countries?