to some of the most beautiful spots in cities around the world:

Rome's Spanish steps;

the historic neighborhoods of Paris and Shanghai;

the rolling landscape of Central Park;

the tight-knit blocks of Tokyo or Fez;

the wildly sloping streets of the favelas of Rio de Janeiro;

the dizzying step wells of Jaipur;

the arched pedestrian bridges of Venice.

Now let's go to some newer cities.

Six downtowns built across six continents in the 20th century.

Why do none of these places have any of the charming characteristics

of our older cities?

Or let's go to six suburbs built on six continents in the 20th century.

Why do none of them have any of the lyrical qualities

that we associate with the places that we cherish the most?

Now, maybe you think I'm just being nostalgic --

why does it matter?

Who cares if there is this creeping sameness besetting our planet?

Well, it matters because most people around the world

are gravitating to urban areas globally.

And how we design those urban areas could well determine

whether we thrive or not as a species.

So, we already know that people who live in transit-rich areas,

live in apartment buildings,

have a far lower carbon footprint

than their suburban counterparts.

So maybe one lesson from that is if you love nature,

you shouldn't live in it.

(Laughter)

But I think the dry statistics

of what's known as transit-oriented development

only tells part of the story.

Because cities, if they're going to attract people,

have to be great.

They have to be powerful magnets with distinctive appeal

to bring in all those new green urbanites.

And this is not just an aesthetic issue, mind you.

This is an issue of international consequence.

Because today, every day,

literally hundreds of thousands of people are moving into a city somewhere,

mainly in the Global South.

And when you think about that, ask yourself:

Are they condemned to live in the same bland cities

we built in the 20th century,

or can we offer them something better?

And to answer that question,

you have to unpack how we got here in the first place.

First: mass production.

Just like consumer goods and chain stores,

we mass-produce glass and steel and concrete and asphalt and drywall,

and we deploy them in mind-numbingly similar ways across the planet.

Second: regulation.

So, take cars, for instance.

Cars travel at very high speeds.

They're susceptible to human error.

So when we're asked, as architects, to design a new street,

we have to look at drawings like this,

that tell us how high a curb needs to be,

that pedestrians need to be over here and vehicles over there,

a loading zone here, a drop-off there.

What the car really did in the 20th century

is it created this carved-up, segregated landscape.

Or take the ladder fire truck -- you know, those big ladder trucks

that are used to rescue people from burning buildings?

Those have such a wide turning radius,

that we have to deploy an enormous amount of pavement, of asphalt,

to accommodate them.

Or take the critically important wheelchair.

A wheelchair necessitates a landscape of minimal slopes

and redundant vertical circulation.

So wherever there's a stair, there has to be an elevator or a ramp.

Now, don't get me wrong, please -- I am all for pedestrian safety,

firefighting

and certainly, wheelchair access.

Both of my parents were in wheelchairs at the end of their lives,

so I understand very much that struggle.

But we also have to acknowledge that all of these well-intentioned rules,

they had the tremendous unintended consequence

of making illegal the ways in which we used to build cities.

Similarly illegal: at the end of the 19th century,

right after the elevator was invented,

we built these charming urban buildings,

these lovely buildings, all over the world,

from Italy to India.

And they had maybe 10 or 12 apartments in them.

They had one small elevator and a staircase that wrapped them

and a light well.

And not only were they charming buildings that were cost-effective,

they were communal --

you ran into your neighbor on that stairwell.

Well, you can't build this, either.

By contrast, today, when we have to build a major new apartment building somewhere,

we have to build lots and lots of elevators

and lots of fire stairs,

and we have to connect them with these long, anonymous, dreary corridors.

Now, developers -- when they're confronted with the cost

of all of that common infrastructure,

they have to spread that cost over more apartments,

so they want to build bigger buildings.

What that results in is the thud,

the dull thud of the same apartment building being built

in every city across the world.

And this is not only creating physical sameness,

it's creating social sameness,

because these buildings are more expensive to build,

and it helped to create an affordability crisis

in cities all over the world, including places like Vancouver.

Now, I said there was a third reason for all this sameness,

and that's really a psychological one.

It's a fear of difference,

and architects hear this all the time from their clients:

"If I try that new idea, will I be sued?

Will I be mocked?

Better safe than sorry."

And all of these things have conspired together

to blanket our planet with a homogeneity that I think is deeply problematic.

So how can we do the opposite?

How can we go back to building cities

that are physically and culturally varied again?

How can we build cities of difference?

I would argue that we should start

by injecting into the global the local.

This is already happening with food, for instance.

You just look at the way in which craft beer has taken on corporate beer.

Or, how many of you still eat Wonder Bread?

I'd bet most of you don't.

And I bet you don't because you don't want processed food

in your life.

So if you don't want processed food,

why would you want processed cities?

Why would you want these mass-produced, bleached places

where all of us have to live and work every day?

(Applause)

So, technology was a big part of the problem in the 20th century.

When we invented the automobile, what happened is,

the world all bent towards the invention.

And we recreated our landscape around it.

In the 21st century,

technology can be part of the solution --

if it bends to the needs of the world.

So what do I mean by that?

Take the autonomous vehicle.

I don't think the autonomous vehicle is exciting because it's a driverless car.

That, to me, only implies

that there's even more congestion on the roads, frankly.

I think what's exciting about the autonomous vehicle is the promise --

and I want to stress the word "promise,"

given the recent accident in Arizona --

the promise that we could have these small, urban vehicles

that could safely comingle with pedestrians and bicycles.

That would enable us to design humane streets again,

streets without curbs,

maybe streets like the wooden walkways on Fire Island.

Or maybe we could design streets with the cobblestone of the 21st century,

something that captures kinetic energy, melts snow,

helps you with your fitness when you walk.

Or remember those big ladder fire trucks?

What if we could replace them and all the asphalt that comes with them

with drones and robots that could rescue people from burning buildings?

And if you think that's outlandish, you'd be amazed to know

how much of that technology is already being used today

in rescue activity.

But now I'd like you to really imagine with me.

Imagine if we could design the hovercraft wheelchair.

Right?

An invention that would not only allow equal access,

but would enable us to build the Italian hill town of the 21st century.

I think you'd be amazed to know

that just a few of these inventions, responsive to human need,

would completely transform the way we could build our cities.

Now, I bet you're also thinking:

"We don't have kinetic cobblestones or flying wheelchairs yet,

so what can we do about this problem with today's technology?"

And my inspiration for that question comes from a very different city,

the city of Ulaanbaatar, Mongolia.

I have clients there

who have asked us to design a 21st-century open-air village

that's sustainably heated using today's technology,

in the heart of their downtown.

And that's to cope with their frigid winters.

And the project is both poetry and prose.

The poetry is really about evoking the local:

the mountainous terrain,

using colors to pick up the spectacular light,

understanding how to interpret the nomadic traditions

that animate the nation of Mongolia.

The prose has been the development of a catalogue of buildings,

of small buildings that are fairly affordable,

using local construction materials and technology

that can still provide new forms of housing,

new workspace,

new shops

and cultural buildings, like a theater or a museum --

even a haunted house.

While working on this in our office,

we've realized that we're building upon the work of our colleagues,

including architect Tatiana Bilbao, working in Mexico City;

Pritzker laureate Alejandro Aravena, working in Chile;

and recent Pritzker winner Balkrishna Doshi, working in India.

And all of them are building spectacular new forms of affordable housing,

but they're also building cities of difference,

because they're building cities that respond to local communities,

local climates

and local construction methods.

We're doubling down on that idea, we're researching a new model

for our growing cities with gentrification pressures,

that could build upon that late-19th-century model

with that center core,

but a prototype that could shape-shift in response to local needs

and local building materials.

All of these ideas, to me, are nostalgia-free.

They all tell me

that we can build cities that can grow,

but grow in a way that reflects the diverse residents

that live in those cities;

grow in a way that can accommodate all income groups,

all colors, creeds, genders.

We could build such spectacular cities that we could disincentivize sprawl

and actually protect nature.

We can grow cities that are high-tech,

but also respond to the timeless cultural needs of the human spirit.

I'm convinced that we can build cities of difference

that help to create the global mosaic to which so many of us aspire.

Thank you.

(Applause)