Photo by Nick Blumberg - KJZZ

Colleen Jennings-Roggensack has served as Gammage's executive director for more than 20 years.

Photo by Nick Blumberg - KJZZ

Jennings-Roggensack looks up at the balconies inside the auditorium, which are not connected to the back wall.

(Photo by Nick Blumberg - KJZZ)

Looking down from the highest point in Gammage.

Photo by Nick Blumberg - KJZZ

Underneath Gammage's stage, which is equipped with several cutouts for trap doors.

Photo by Nick Blumberg - KJZZ

The glamour of a Gammage dressing room.

Photo by Nick Blumberg - KJZZ

Structural elements that Wright referred to as his "elephants" run along the pedestrian ramps on either side of Gammage, and they run all the way into the interior of the building.

Photo by Nick Blumberg - KJZZ

Dean Victor Sidy of the Frank Lloyd Wright School of Architecture.

One of Arizona's architectural icons is celebrating its 50th anniversary this year. Grady Gammage Memorial Auditorium, better known just as Gammage, is the last major public building designed by the legendary Frank Lloyd Wright.

"Over 50 years ago, President Grady Gammage and Frank Lloyd Wright walked the campus of Arizona State University," said Colleen Jennings-Roggensack, ASU Gammage's executive director. "President Gammage was stopped by Frank Lloyd Wright."

Wright put a cane in the ground and said, "I believe this is the site."

Wright envisioned a circular building with long pedestrian ramps on either side that look like outstretched arms. The bulk of the design was originally for an opera house on the Tigris River in Baghdad.

Both Wright and Gammage died before the building was completed in 1964, but the project they championed still stands. It hosts big-name Broadway shows, such as "Phantom of the Opera," "The Lion King" and "Wicked" to name a few. It's also home to the ballet, the symphony and the orchestra.

But it's not just what happens on the stage that's of interest. It's also Frank Lloyd Wright's sometimes surprising design. Jennings-Roggensack pointed out one of her favorite parts of the auditorium.

"These balconies are free-standing balconies, they are not adhered to the back wall. I just think this is one of the most elegant parts. If you've ever been in the big sand dunes in the desert, that's what it reminds me of. It just has these wonderful sweeping lines," Jennings-Roggensack said.

Under the stage in a maze of hallways, things aren't quite as breathtaking. We look inside a cramped room set aside for the star of the show.

"People always say, 'Oh, life on the road! This must be glamorous!' So you can see, this is a what a star dress looks like. It's very glamorous!"

To learn more about Gammage, I went up to Taliesin West in North Scottsdale to meet Victor Sidy. He's the dean of the Frank Lloyd Wright School of Architecture.

Sidy said Gammage shows Wright's fascination with interior and exterior.

"In an auditorium, you have an odd problem," Sidy said. "You have to, in a way, shut out the outdoors — the ambient noise, the cars that are roaring along Apache, for example. I think what Wright did was, in this case, turn the interior into this kind of a cocoon or a nest or something."

But, Sidy said when you're in the lobby, the huge glass walls make it feel almost like you're outside.

"That is a huge transformation of the auditorium from, say, what you would have seen 50 years prior," Sidy said of older theatres that were closed off and imposing, with a grand staircase. "Only the elite (got) to go inside the building, whereas in Gammage it's quite an egalitarian building. There's a sense of democracy. Architecture for democracy was something that Wright was fascinated by."

While Wright was fascinated by architecture, Colleen Jennings-Roggensack said, "He knew nothing about ladies' toiletry. Like, nothing!"

She showed me one of the women's restrooms off the lobby of the uppermost floor. "There are four toilets. There are 3,017 people here!" Jennings-Roggensack said.

Gammage has started to raise money for renovations and upgrades, such as adding more toilets and improving electronic sound quality. But these changes, and the 50th anniversary of a historic building like Gammage, bring up important questions for Taliesin West's Victor Sidy.

"One of the challenges is, do you fix (the building) as in amber, in a way that is immutable and unchanging? Or do you look at the life that it represents, that it was originally designed for, the functions that it requires and design around that? And I would lean a little bit more toward the latter approach," Sidy said.

As an architect, Sidy doesn't think Gammage is quite as refined as some of Wright's other work. He points out that parts of the auditorium are an interpretation of Wright's ideas, because he didn't live to see it finished.

"But it is a public space, and it's a fantastic opportunity for all of us to get to know the work of Frank Lloyd Wright," Sidy said.