How do we need to build in the future?
Well, the first thing I would say is you can't build the same way in each city. And we are now making the same mistake that the International Style did in the second half of the 20th century - the "glass boxes," everybody calls them. Well, if you go to Dubai or you go Shanghai, the buildings look exactly the same. The climate is quite different: one is in a desert, the other one is not. One is the commercial capital of the world already, and has been for a century or more, the other one is becoming. So I would argue the first thing we have to do is take into account local conditions. I have just been in Bath. I would not suggest building in Bath what you would build in Dakar, or what you would build, for that matter, in New York City. These are very different places, and what is sustainable in one climate and in one topography and in one culture is different from another.

What lessons have we learned in the developed world?
The most important thing is the public realm. That is to say, the streets, the parks, the public buildings - that part of the city that the public owns and uses. And that ought to be the framework. And where you have a great public realm, you determine the city. Nobody can think of Paris without the grands boulevards. In fact, the very idea of a boulevardier sitting in a café in Paris is something that is astonishing. And that framework is what created Paris, along with the parks in London; the royal parks are something that is quite unique. I would say the most important thing is to determine what that public realm ought to be, how it adapts to the culture of the country involved. Because I don't believe that what one does in Paris is one should be doing in Venice. It's a very different place - the climate, the geography, and the culture. And yes, you could have outdoor cafés in both places, but I'm not sure that outdoor cafés are something that's easy to do in Alaska. And I could go on. The lifestyle in the United States is quite different. That's the first thing.

The second thing I would say is a great public transportation system. To that degree, if you look at the impact of the Jubilee Line in London or the Metro in Washington going out into Maryland, they have spawned a totally new kind of development all the way along. And creating that great public transit system, I think, is essential.

What's your vision of a perfect city?
You know, there are wonderful old images of perfect cities. I don't believe in them. I think that's the problem. I don't believe that people who live in Glasgow should live in the same kind of place as the people who live in Cairo. I don't believe the culture is the same. I don't believe the people in Glasgow want to live the way people live in Bristol or New York City. And so, when I'm asked about ideal cities, my reaction is, that that should be left to the books. But cities themselves have to have their own personality and reflect the people that live there.

Are architects becoming more important?
Project yourself back into 15th century Florence, when they were building a cathedral, and they didn't know how to put a covering over the crossing in the church until Brunelleschi came along and determined how you could build a dome on top of the cathedral. That's not so different from our situation today. Moreover, Brunelleschi was a star in the city, not unlike Daniel Libeskind or Norman Foster or Frank Gehry. And in fact, I believe we are going back to a period in which some of the architects are that sort of star. And I'm very proud of the fact that by having the competition that we did for Lower Manhattan, we accelerated that process in the United States.

I think it's very, very important to have great art. And architects produce that great art. And in the end, what's the difference? Bernini, Michelangelo, Brunelleschi - these were figures of extraordinary talent and were, in their day, admired by their culture and by the people who lived in the cities that were lucky enough to get their works. I don't think it's very different today. You know, Bilbao has this extraordinary museum that Frank Gehry has done. I am sad that we have yet to see a great building by Daniel Libeskind in New York City. But they're going up all over the world. I was in a great museum in Denver, I was in another one in Manchester, in England. They are going up. The same thing is true of Frank Gehry and the Disney Hall now in Los Angeles. I believe we've turned a corner, and we are going to see increasingly some imaginative buildings by great designers.