Aristotle

Philosopher and Polymath

Aristotle was the citizen who tried to explain everything and more - and almost succeeded). He was born in 384 BC in Greece, was a disciple of Plato and tutor to Alexander the Great. He was the kind of guy who wasn't content with knowing just a little bit - he dabbled in philosophy, biology, politics, ethics, physics and even the art of complicating simple concepts.
 

He founded the Lyceum, a school where he and his students walked around philosophising (probably the first to practice ‘walking meetings’). His ideas influenced Western thought for centuries, even when they were wrong (like the story that heavy objects fall faster). He died in 322 BC, but he left behind so much theory that even today people are still trying to understand what he meant.