At the beginning, I thought the best Islamic work was in Spain - the mosque in Cordoba, the Alhambra in Granada. But as I learned more, my ideas shifted. I traveled to Egypt, and to the Middle East many times.I found the most wonderful examples of Islamic work in Cairo, it turns out. I'd visited mosques there before, but I didn't see them with the same eye as I did this time. They truly said something to me about Islamic architecture.

I know something about the civilization of China, with my background, obviously, and I think I know something about American history. But that's about all. And I've traveled all over the world, and for a long time I didn't know very much about it, really.

My projects have typically taken a long time to complete. Buildings might take on average about five to seven years to finish, but in my case it's been longer, because the projects I have accepted within the past 15 years have been mostly government projects, and those involve some politics and funding issues, and approvals and so forth. So they're slower.

François Mitterrand was a student of architecture, he had done a lot of research before he called me. He said, "You did something special at the National Gallery of Art in Washington - you brought the new and the old together." But John Russell Pope finished the West Building in 1941, so when the East Building opened it was only about 40 years old. But the Louvre is 800 years old! A much bigger design challenge.

I didn't want to think about a project that I couldn't finish. That's a kind of temptation. One has to realize one's limitations. Why kid yourself? 

Qatar does not have much history, it's a new emirate. So I couldn't draw on the history of the country; its history is really just being a desert. But I thought, the one thing I must learn about for this project is the Islamic faith. So I read about Islam and Islamic architecture, and the more I studied the more I realized where the best Islamic buildings were.

Luxembourg was and still is today a crossroads, the place where Germany meets the rest of Europe. The country lost part of its territory to Belgium in the 1800s, and during World Wars I and II the German military overran it. Very few people have visited Luxembourg - when I went there and looked at it, I said, my God, it's built on a rock. And within the rock they had a castle, and within the city there's a network of tunnels so the residents could move around and defend themselves. That was of great interest to me.