Michael Bloomberg vs. Elon Musk

In 2018, Bloomberg pledged $1.8 billion to Johns Hopkins University, his undergraduate alma mater, adding $1.5 billion he had already given the school. As a teenager, Bloomberg worked at an electronics company in Cambridge, Massachusetts.

Musk, who says he's worried about population collapse, has nine children with three women, including triplets and two sets of twins. As a kid in South Africa, Musk taught himself to code; he sold his first game, Blastar, for about $500.