The celebrated architect Frank Gehry, who at 85 is just one year younger than the Philadelphia Museum of Art, visited the city Thursday to kick off a special exhibition detailing his plans for expanding the iconic museum building.

While he has worked on the project for a decade, the museum is only now unveiling the design, which involves carving out a block-size space under the east terrace to create a new wing of galleries.

Most of the improvements will be out of public view, except for two controversial proposals. Gehry wants to insert a large picture window in the so-called Rocky steps across from Eakins Oval to bring light into the new underground galleries; and, because the museum does not meet modern safety requirements, he would build a matched pair of free-standing fire stairs on the museum's east-facing wings.

Drawings, models and photographs of these changes, and the rest of Gehry's design, will be on view from Tuesday through Sept. 1 in "Making a Classic Modern: Frank Gehry's Master Plan for the Philadelphia Museum of Art."

After Gehry's museum visit, he sat down for a chat about his plan. Here are excerpts, condensed and edited for clarity:

Question: Did you have qualms about tampering with the beloved Rocky steps?

Answer: I promised Annie [the museum's late director, Anne D'Harnoncourt] that I wouldn't do anything drastic on the outside of the building. But board member Mark Rubenstein gave me the idea cutting in a window. He said you could get a great view of City Hall [from the underground galleries]. I said, 'Do you think we could really do that?' And he said yes.  

Q: You would also, in the area around the window, create a small amphitheater about halfway up the grand staircase, right? 

A: We're trying to be discreet, and we're still studying this. There are 10 different ways to do it. It's not a done deal by any means. It's something we resisted doing. But it's powerful, because in one simple move it changes the character of the galleries.

Q: How were you hired by D'Harnoncourt, who died in 2008? 

A: We were walking through the Barnett Newman show [in 2002] together. I was with Ellsworth Kelly - these are the artists of my generation, my family - and Anne said we need to do something special in Philadelphia. She asked me, would I do it? . . . And I just want to say, now, thank you for letting me do it. 

Q: How does it feel to tinker with such an iconic art museum? 

A: It's an extraterrestrial experience, transcendent. I feel like I'm collaborating through time with [museum architects] Horace Trumbauer and Julian Abele. It's an amazing experience. The DNA of this building is so powerful. . . . I'm ready to put this building up against [New York's Metropolitan Museum of Art] any day. The Met has these endless corridors. This is compact. [Trumbauer and Abele] created a very readable and understandable structure. Usually architects create a closed system, but in this case they built in the ability to play vertically and horizontally.

Q: You're known for your signature swooping curves, yet here you've toned down your style and employ mostly straight lines. Why? 

A: I'm not changing very much. There was a question of how much intervention. I don't think you need architectural flourishes. I like that you'll pass by and not know Frank Gehry was there. But when it's done, it will be a big surprise to people who think they know the building.  

Q: Your stair towers design is especially understated - they'll be 22 feet wide and 35 feet tall, roughly the size of a Philadelphia townhouse, and clad in the same kasota limestone as the museum. Since you are required to cut into the historic facade, why not use the opportunity to do something more playful? 

A: No one has ever accused me of holding back before. My mission was to preserve the appearance of the exterior. Anything I'd do to put my signature on the building would be trivial. But it would be beautiful in glass. 

Q: Has any other project every taken you as long as this one, which may not be finished until 2028, when the museum is 100 and you are 99? 

A: The Disney Hall [in Los Angeles] took 12 years, but that was because of poor management. I wish this would go faster. But they need to raise the money [$156 million for the first phase, and a total of more than $350 million]. I wonder if people in Philadelphia know what a big deal this is? Bilbao was a sleepy little town before the Guggenheim came along. This is going to change Philadelphia.


Inga Saffron reviews of the plans for expansion at