This is 99% invisible. I'm Roman Mars.

Humans have been living in cities for a really long time,

but like a lot of things about the past,

getting around cities used to be just needlessly difficult because

we didn't have reliable maps or street signs or even addresses.

An address is something we all take for granted today. But in ancient Rome, if you

wanted to go to a friend's house, you had to use all kinds of context clues. Like you had to remember

that the house was two blocks away from a big column, but if you reach the horse stables, you'd gone too far.

And you had to rely on non-visual cues, like smells and noises.

You had all sorts of noise and street hawkers

and you had different smells,

you had the smell of a meat market.

Yes, sometimes you had to use meat smells to figure out where you were going.

Maybe one of the ways you navigate is you navigate much more by your senses. You can actually use what you're seeing and what you're smelling and what you're hearing as a ways of navigating around the city.

This is Deutramask. I'm the author of the address book, What Street Addresses Reveal about identity, race, wealth, and power.

Deirdre's book looks at how the world has changed since street addresses became popular during the Enlightenment.

So today, we're going to take a tour through some of the many ways street addresses shaped our lives, including how we fight disease.

54 Frith Street, London, England, the Office of Dr. John Snow.

So street addresses come up in the 1700s and they

revolutionized was our approach to public health.

So can you tell me how addresses related to the cholera epidemic in London.

A doctor called John Snow, this is in the Victorian London.

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