You might easily mistake him for a crazy dude spouting gibberish on the corner, but Tiresias was totally legit. This old, blind man was a priest of Apollo and one of the most famous seers of all time. He could hear the future in the songs of birds (a little trick called augury), and he also received visions sent to him by the gods. Tiresias used his powers to advise seven generations of kings in his hometown of Thebes, though they had a tendency not to listen to what he had to say until it was too late. (We're looking at you, Oedipus and Creon.)

Even after Tiresias died by drinking from the poisoned water of Tilphussa, he had tons of power. Odysseus himself made a pit stop in the Underworld to get some travel advice from Tiresias, without which the O-man never would've made it home. Tiresias may have been a rough looking dude with a tendency to speak in cryptic riddles, but in the end, he was totally worth listening to.