Welcome to the inquiry on the BBC World Service with me, Kavita Puri.

Each week, one question, four expert witnesses and an answer.

New York, the city that never sleeps. Home to 8 million people, it's loud, vibrant and has attitude. But COVID-19 brought a silence

to the streets, interrupted only by ambulance sirens. And then something strange happened, instead of the taxi horns,

cars and the chatter of New Yorkers.

You could hear the birds and spot a red-tailed hawk nest on the ledge of a high-rise skyscraper.

And as cities across the world went into lockdown, from frigate birds in Rio de Janeiro to lesser

castrals above Seville's Cathedral and pied kingfishers over Cairo, nature returned.

Cities were transformed not only with wildlife, but there were no cars, clean air. You could see the stars at night.

And as lockdown's now ease, with cities stirring once again, people are asking, will they ever be the same and do we want them to be?

So this week on the inquiry we ask, will COVID-19 change cities?

Part 1, a new enemy. I have been obsessed all my life.

Beatrice Kolomina is professor of architecture at Princeton University in the United States.

She's from Madrid in Spain but's been living in America for around 40 years.

It's probably one of those inherited obsessions of a former generation, the generation of my parents

who were still obsessed with tuberculosis, with typhoid fever with all these diseases that were still

killing a lot of people. This obsession has informed the focus of Professor

Colomina's research, the relationship between disease and cities.

You could argue that the history of the cities is the history of disease.

Take tuberculosis, unlike cholera, which was eliminated in London by redesigning the

sewage system in the 1850s, TB was airborne.

But it became really a problem with the rise of the industrial cities, the metropolis,

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