Mansa Musa I of Mali is the richest human being in history with a personal net worth of $400 billion! Mansa Musa lived from 1280 - 1337 and ruled the Malian Empire which covered modern day Ghana, Timbuktu and Mali in West Africa. Mansa Musa's shocking wealth came from his country's vast production of more than half the world's supply of salt and gold. Musa used his wealth to build immense mosques that still stand today, nearly 700 years later. His kingdom and wealth didn't last much longer after his death. His heirs were not able to fend off civil war and invading conquerors. Just two generations later, his world record net worth was gone.