Gio Ponti’s only building in the United States, for the Denver Art Museum (DAM), will turn 50 in 2021. DAM announced today a $150 million upgrade and addition to the seven-story tower—one of the first high-rise art museums—to be completed in time to mark the special anniversary.

Denver-based Fentress Architects and Machado Silvetti will lead the renovation project, which includes aspects of Ponti’s original design that were never realized. “Ponti had planned an ellipse-shaped auditorium that did not get built,” says DAM director Christoph Heinrich. “We have an auditorium now in Daniel Libeskind’s Hamilton building, but will reintroduce that shape as a welcome and education center. It works beautifully between the zig-zagging form of Libeskind’s building and the castle-like structure of Ponti’s.” The new addition will take cues from Ponti’s design but will be smaller and more open and light-filled.

Within the tower, Ponti intended the seventh floor to have lookout spaces to take advantage of stunning views of the Rocky Mountains to the west, and of downtown Denver to the south. Such spaces will be added as that floor is transformed into galleries for the museum’s expanding collection of Western American Art.

DAM has spent considerable sums in the past decade on new buildings—practically rivaling what much larger museums in New York and San Francisco have expended for new construction and renovation projects in that same time period. The Hamilton Building, completed in 2006, cost $100 million. And just two years ago, DAM moved its administration offices into a new $12 million building on the campus.

Denver, though, has seen tremendous growth in recent years. When Ponti’s building was completed in 1971, annual visitors to the museum totaled 100,000. Today the number is more than seven times that. “The role of a museum, especially in a medium-sized city, is that of a community center and catalyst,” says Heinrich. “Of course it’s more fun to build something new for the money we’re spending, and a big-name architect might attract attention, but we’re not looking for national buzz that lasts a few weeks. We needed the right offering and the right services. Fentress and Machado Silvetti can get the job done and stay on budget, and they bring a profound knowledge of Ponti’s work.”

“Ponti is an architect and designer I’ve admired all my life; he’s unrecognized in this country, even ignored,” says Jorge Silvetti. “This project is a synthesis of all the issues we really love—preservation, cultural heritage of cities and bringing that into the 21^st century, creation of public space—in a city that has changed dramatically.”

Ponti’s building has 24 different sides, all covered with over one million tiles of reflective gray glass. “Every year a few of them pop off,” jokes Curtis Fentress. The renovation aspect also includes upgrading building systems, adding elevators, and making the building compliant with current ADA and fire codes. “The safety and security of visitors and of the collection is a priority,” Heinrich says.

On a grander scale, according to Fentress, the project presents a new front door to the 14-acre museum complex. “It is a very important site in Denver, and one that we’ll tackle in the spirit of Ponti.”