Hello everyone, welcome to the Mindscape Podcast.

I'm your host, Sean Carroll.

This is kind of an obvious thing to say, but cities play an increasingly important role

in the modern world.

We've talked about cities a few times on Mindscape.

We talked to Will Wilkinson about the relationship between urban versus rural and political

partisanship.

We talked to Joe Walston about the environmental impacts of cities, which are largely positive,

concentrating all of the people and their products and resources in a tiny area.

But the cities themselves, we haven't talked about that much, the growth of a city, the

shape of a city.

The UN estimates that by 2050, more than two-thirds of the global population will live in cities.

So understanding how they grow, how they form, how their shape becomes what it is, is

very important.

And by the shape, I don't just mean the shape of the boundary of the city limits, right?

Inside the city, there is structure.

The central core downtown area might have a different mix of residential and businesses

and manufacturing than the outer periphery does.

And what I like about this question is, it's a wonderful example of the differences between

top down and bottom up ways of making a complex system.

Because in some sense, the natural growth of a city is completely organic, right?

You have people, they want to buy some land, build something, put up some way of living

...