One of the biggest misperceptions about places of genius, though, is that they are akin to paradise. To the contrary, ancient Athens was a place of public opulence and private squalor. The streets were noisy, narrow, and dirty. The houses of the wealthy were indistinguishable from those of the poor, and both were equally shoddy—constructed of wood and sun-dried clay, and so flimsy that robbers gained entry by simply digging.

How did a small, dirty, crowded city, surrounded by enemies and swathed in olive oil, manage to change the world? Was Athenian genius simply the convergence of “a happy set of circumstances,” as the historian Peter Watson has put it, or did the Athenians make their luck? This question has stumped historians and archaeologists for centuries, but the answer may lie in what we already know about life in Athens back in the day.

The ancient Athenians enjoyed a deeply intimate relationship with their city. Civic life was not optional, and the Athenians had a word for those who refused to participate in public affairs: idiotes. There was no such thing as an aloof, apathetic Athenian. “The man who took no interest in the affairs of state was not a man who minded his own business,” wrote the ancient historian Thucydides, “but a man who had no business being in Athens at all.” When it came to public projects, the Athenians spent lavishly. (And, if they could help it, with other people’s money—they paid for the construction of the Parthenon, among other things, with funds from the Delian League, an alliance of several Greek city-states formed to fend off the Persians.)

All of ancient Athens displayed a combination of the linear and the bent, the orderly and the chaotic. The Parthenon, perhaps the most famous structure of the ancient world, looks like the epitome of linear thinking, rational thought frozen in stone, but this is an illusion: The building has not a single straight line. Each column bends slightly this way or that. Within the city walls, you’d find both a clear-cut legal code and a frenzied marketplace, ruler-straight statues and streets that follow no discernible order.

In retrospect, many aspects of Athenian life—including the layout and character of the city itself—were conducive to creative thinking. The ancient Greeks did everything outdoors. A house was less a home than a dormitory, a place where most people spent fewer than 30 waking minutes each day. The rest of the time was spent in the marketplace, or working out at the gymnasium or the wrestling grounds, or perhaps strolling along the rolling hills that surround the city. Unlike today, the Greeks didn’t differentiate between physical and mental activity; Plato’s famous Academy, the progenitor of the modern university, was as much an athletic facility as an intellectual one. The Greeks viewed body and mind as two inseparable parts of a whole: A fit mind not attached to a fit body rendered both incomplete.