Source: dccomics.com

4. Mr. Terrific (Michael Holt)

In a competition for smartest man on earth, bronze ain't bad. Michael Holt is notably the third-smartest man in the DC Universe (at least, in the present day time period).

After Bruce Wayne and Lex Luthor, the enforcer of Fair Play clocks in at third. Michael was a child prodigy with an aptitude for brilliance who mastered multiple skill sets and claimed 14 PhDs. Dude collected doctorates like they were Pokemon cards. He started a tech firm and won a gold medal in the Olympic decathlon.

Tragically, Holt lost his wife and older brother in a car accident, and he began to contemplate suicide. The Spectre intervened, and inspired him to instead use his life to help others as the new Mr. Terrific.

In spite of this experience, Holt remained a devout atheist. Look, in the real world, your religious beliefs are up to you. But in the DC Universe, Michael Holt literally met the agent of God's vengeance – a ninety-foot-tall ghost man with torture powers – and was still like, "Nah, I'm not convinced." At that point, it's almost respectable.