For Pei, that meant looking beyond the American geography that had dominated his imagination since the 1950s: his postretirement projects have taken him to Japan, Spain, Greece, England, Germany, Luxembourg, China, and Macao. Although Pei began working on the Louvre while he was still a full partner at the firm, the time he spent in France spurred him to venture even farther from his New York City base.

"I'd been going to the Louvre since 1951. I thought I knew Paris and the French, but I didn't really," he says. "You know how easy it is to make friends when you are traveling. People are curious about you, you are curious about them. But you never really make friends that way. After the Louvre, I discovered that I have friends now because I have enemies. Unless you fight, unless you really confront each other with differences of opinion, you don't really know each other. That project gave me a wake-up call. It said, 'If you are truly interested in the world, you have to work there.' So I said, Now that I am retired, I am going to learn something about the world. It's not too late. I'm still here."

And he's still going back to Paris, where the Louvre now needs interior changes to accommodate growing crowds. "If you go under the pyramid, it looks like an airport," he says, noting that the museum now draws more than eight million people a year, up from about four to five million when he started working on the expansion and modernization in 1983. When asked what he thinks about the idea of Mary Magdalene being buried beneath his famous inverted pyramid, as was suggested in The Da Vinci Code, he scoffs and says, "Fiction," but he is smiling as he says it. "The movie wasn't very good. Disappointing. The book was better." But The Da Vinci Code, he points out, "is part of the reason for the eight million people coming to the Louvre." And he smiles again.

Pei, who comes from a prominent Chinese family, grew up in Hong Kong and Shanghai; he left China in 1935 and became an American citizen in 1954. When he came to the United States for college, however, he had no idea that global politics would keep him from returning to China for nearly 40 years.

He still feels the pull of his homeland. "You have to give up one citizenship in order to acquire another one. That's the only honest thing to do," he says in the 1997 documentary First Person Singular: I. M. Pei. "But it was really difficult for me to give up China." Upon winning the Pritzker Architecture Prize in 1983, he used the $100,000 award to establish a fund to help Chinese students study architecture in the United States, with the stipulation that they return to China. And when hundreds of people were killed in the Tiananmen Square protests of 1989, Pei was so distressed that he wrote a piece deploring the violence, titled "China Won't Ever Be the Same," for the New York Times. In 1990, he cofounded the Committee of 100 to foster relations between citizens of the United States and China.