SHIRLEY GRIFFITH: For economist Edward Glaeser, the best place to live is a city.
EDWARD GLAESER: "Cities are so fascinating because they play to mankind's greatest gift, which is our ability to learn from other people."
Since ancient times, he says, cities have given creative minds a place to work together to improve societies. But cities have not always gotten much thanks in return.
EDWARD GLAESER: "In the nineteen seventies, it looked as if globalization, new technologies and the death of distance was making our older cities obsolete. After all, the garment industry was fleeing New York. It looked like history itself was telling New York City to drop dead."
Yet since then, he says, globalization and new technologies have driven improvements in many cities. As a result, people are better able to profit from ideas.
EDWARD GLAESER: "What these new forces have done is they've increased the returns to new ideas, to being smart, because now if you got a new idea, you can manufacture it on the other side of the planet, you can take advantage of some new market opportunity in India, or Indonesia or Sub-Saharan Africa. These trends have also made cities more important because cities are at their heart today, engines of innovations, forgers of human capital."
Penguin
Edward Glaeser has written a new book called "Triumph of the City." He takes readers on a world tour of what he considers urban success stories, from Boston, London and Tokyo to Bangalore and Kinshasa.
Mr. Glaeser is a professor at Harvard University. He himself lives outside the city of Boston.
Big cities can seem impersonal. They can be crowded, dirty and dangerous, but also places of pleasure and production. Mr. Glaeser says restaurants, supermarkets, theaters and museums all play a part in creating jobs.
EDWARD GLAESER: "If you look across the world, the countries where more than half of the people live in urban areas are more than four times richer on average than the countries where less than half of the people live in urban areas."
Mr. Glaeser says areas of poverty in cities are really a sign of the power of cities.
EDWARD GLAESER: "Cities don't make people poor, they attract poor people. And they attract poor people by delivering a path out of poverty and to prosperity, a chance to partner with people who have different skills, access to world markets, access to capital that enables poor people, some of them -- not all of them -- to actually find a way forward."
He says cities are also better for the environment.
EDWARD GLAESER: "There is significantly less carbon usage in cities. There are two reasons for that, one of which is less driving; they are more likely to use public transportation. And when they drive, they drive shorter distances. And the second is that people in the cities occupy smaller homes than people living in rural areas."
Not surprisingly, Professor Glaeser thinks even more people should move to cities. He says developing high-rise buildings, or "building up," is a way to avoid developing wider areas, or "building out."
STEVE EMBER: But architect and urban designer Michael Mehaffy says research suggests that the buildings do not have to be very tall.
MICHAEL MEHAFFY: "It might only require four, six, eight stories, something like that, to get very good urban densities and to have a very vital urban environment."
Mr. Mehaffy also says high-density living does not always improve quality of life.
MICHAEL MEHAFFY: "There is a point where more density doesn't really get you very much. I mean, it can be very helpful in some circumstances, it can be very destructive in some circumstances. I think we should really focus on what urban living gives to us in the network of relationships, not so much an abstract number like density and 'Let's just make it absolutely as high as possible and let's have tall buildings.' Because once you do that, you start to kick in a lot of negative effects from density."
Michael Mehaffy also points out that not everyone enjoys life in the big city.
MICHAEL MEHAFFY: "Not everybody kind of wants to live in a super high-density city. I think people from different political persuasions, and all walks of life are getting more interested in more connected urban environments, and that isn't necessarily just big cities."
In this world of seven billion people, a United Nations report says the population balance has tipped in favor of cities and away from rural areas. But it also says there is no easy answer to the question of what exactly a "city" is in twenty-eleven. "Governments and urban areas themselves define 'city' in numerous ways and their boundaries can shift, sometimes for political, demographic or economic reasons."
The U.N. Population Division calls Tokyo and other huge population centers "urban agglomerations." Under that definition, Tokyo is the world's largest urban area. Almost thirty-seven million people live there -- more than one-fourth of Japan's population. Delhi is second, with twenty-two million people, then Sao Paulo and Mumbai. Next are Mexico City; the New York-Newark, New Jersey, area; Shanghai; Kolkata; Dhaka and Karachi.