Today, New York City is filled with lots of all-glass skyscrapers. But when famed architect Frank Lloyd Wright was still alive, no clear, glistening towers loomed over the city's skyline quite yet. Wright tried to change that by designing three glass residential apartment buildings in 1930. If built, they would have stood in a triangular formation around St. Mark's Church-in-the-Bowery in the East Village.

The project never came to fruition, but as Co.Design reports, an architectural model of one of the towers continued to be showcased in international exhibitions. The model survived the decades following Wright's 1959 death, but it was tattered from years of travel—which is why conservationists at the Museum of Modern Art in New York restored it to its former glory before displaying it in a new exhibition of the architect’s work.

"The model came to us in very, very poor condition," conservator Ellen Moody says in the video below, which MoMA filmed to chronicle the restoration process. "It was missing about 50 percent of its exterior; it was covered in soot and grime. It was up to us to bring it to a stable enough condition to be studied and exhibited."

Watch the painstaking process below, or see the restored model in person by visiting the MoMA's ongoing "Frank Lloyd Wright at 150: Unpacking the Archive" exhibit.

[h/t Co.Design]