How Cities Became Humanity’s Engines of Progress (and What Happens When We Close the Gates)

Step into any thriving city today, and you’ll find a living laboratory of progress: markets alive with trade, parks echoing with many languages, and neighborhoods where old meets new. But this isn’t a modern invention—it’s the secret sauce that made cities the engines of human advancement for millennia.



From Uruk and Babylon to Renaissance Florence and Silicon Valley, the world’s greatest leaps in art, science, and technology have come from cities that opened their doors to outsiders and new ideas. The denser the network, the faster ideas spread and combine. Research shows that a city ten times larger is seventeen times more innovative—a testament to the power of connection.

Yet cities are also vulnerable to fear. When crises hit—be it plague, war, or economic shock—leaders sometimes respond by closing gates, raising barriers, and scapegoating newcomers. History is filled with cities that faded into obscurity after turning inward. The lesson? Openness is not just a policy, but a practice—a daily commitment to welcoming difference and nurturing curiosity.



If we want our cities to remain engines of progress, we must defend their openness—not just with laws and institutions, but with a culture that prizes learning, welcomes strangers, and sees every newcomer as a potential friend and collaborator.