5. First named the world's wealthiest in 2007 when he surpassed Warren Buffett and Bill Gates, he has been ranked by Forbes to be the richest man on earth since 2010. At a time, he gained $23 billion in just 14 months. That's like double of Dangote's wealth -in just 14 months! Before he broke the jinx, Americans were the world's richest for sixteen years. Something tells me Dangote may emerge the richest man on earth in a decade or two.