Most of the really rich people in the world have inherited some or all of their money. More than one-third of the richest people in the United States inherited their money from their parents or their spouses. Other rich people are rich because of a combination of inheriting money and earning it. Some heads of government are rich because their countries and families are rich and they have used their money and their position to make more money.
The richest person in the world is probably Sir Mudo Hassanal Bolkiah, the Sultan of Brunei, a small country in Southeast Asia. Brunei gets almost all of its income from oil, and with a population of only about 200,000 people and a cash reserve of more than $30 billion, each citizen of Brunei has a very high income.