The web of pedestrian streets, narrow alleys, and picturesque canals in Venice have lured tourists to the Italian port city for hundreds of years. There’s a near constant hum of activity as people gather in public squares, sit in outdoor cafes, marvel at the ornate architecture, and meander through the labyrinthine city. To Jan Gehl–a Danish architect, writer, and the most respected urbanist alive for his research on how urban design can improve quality of life and curb environmental problems–Venice epitomizes a city that engages all of our senses, and, in effect, becomes an environment tailored for a thriving public life scaled to the individual. It’s the ultimate people-friendly city.

Today, as urban populations swell–by 2050, 66% of the world’s population will live in cities–that notion of “people-friendly” design matters more than ever, Gehl argues. To accommodate growth that is efficient, economically robust, and environmentally sound, planners, politicians, and designers must put people at the center of the city–a point that seems obvious, except when you consider that for the past six decades, most cities have risen up around cars. Consider Brasilia, a sprawling city built for cars in the 1950s as a reflection of modernity and progress–the pinnacle of technological innovation at the time. Devoid of public life in most areas, Brasilia was deemed a “concrete carbuncle” by the BBC.

Rosalba Matta Machado via Shutterstock

“What we have to address now is making livable, healthy, safe, and sustainable cities,” Gehl says. It’s a topic he’s written about in his books Cities for People and Life Between Buildings, and spoken about in The Human Scale, a documentary about his life’s work. His research and theories have inspired a generation of planners and urbanists who are intent on reclaiming cities for people. On the heels of a recent lecture he gave at the Van Alen Institute in New York, we asked him about the most pressing urbanism problems of today and what he thinks the path forward should be.

To Gehl, two of the most pertinent macro issues that city planners can address today are climate change and public health. “For 50 years, we made cities in such a way that people are almost forced to sit down all day in their cars, their offices, or their homes,” he says. “This has led to serious situations health-wise.”

He attributes the problem to cars and the availability of cheap gasoline, which have dictated city planning for the past six decades. “Those factors enabled developed countries to build the enormous suburbs and nobody thought that would be a problem–they thought that [suburbs offered] a good life, this is how it should be done,” Gehl says. “I call it architecture for cheap gasoline. The moment there’s not enough gasoline or it’s not cheap enough, it’s no longer a smart idea. If people get sick of suburban living, it’s not a good idea. I recently read a study in the Lancet, a medical journal, which found that people in suburbs were having shorter lifespans than people who live centrally [in cities] because those who live centrally walk more during their lives than ones who live in the suburbs. There’s a direct effect on the number of good years you have based on where you live. Nobody knew about that, or thought about that, when cheap gasoline and affordable cars were streaming into society.”

In 2009, Copenhagen (where Gehl is based) enacted a plan called “A Metropolis for People,” which was based on Gehl’s work. It envisioned what the city should look like in the future.

“The city council decided upon a strategy to make Copenhagen the best city for people in the world, and it is interesting to read what their arguments are: We have to walk more, we have to spend more time in public spaces, and we have to get out of our private cocoons more,” Gehl says. “This becomes good for society, good for the climate, and good for health. They said that if people spend more time in the public spaces, the city becomes safer. It becomes more exciting and more interesting. And it furthers social inclusion. This is an important part of having a democratic society: having citizens who can meet each other in the course of their daily doings, and not only seeing different people on television or on screens.”