ROCHESTER — David Eide knew from photographs what Presentation Hall looked like when it was built. It featured five pillars surrounded by 4-inch thick granite, art deco brick, a polished metal awning and a granite cornerstone marking the year construction began.

That was the former street-side exterior of the building. When the hall became part of the civic center, that outside wall became part of an inside corridor and was covered up. For decades, no one has seen the former outside of Presentation Hall until workers knocked away some brick to take a peek.

“We had no idea what was under there,” said Eide, senior construction manager at Mayo Clinic.

“The question was, why was it covered up?” he told the Post-Bulletin . “It could have been removed; it could have been damaged.”

There was only one way to find out.

“I was here and said, ‘We’re kind of committed to it — let’s see what’s underneath,’” Eide said.

Workers knocked away the facade. Underneath, they found one of those five columns in near pristine condition. The second one was intact, as were the third and fourth.

The fifth column was damaged. The timing couldn’t have been better. If the damaged column was uncovered first, the restoration project would have halted.

“We probably would have stopped,” Eide said, adding it would have been cost prohibitive to restore all five columns.

“Sometimes luck is on your side,” he said.

The fifth pillar will be repaired using the remaining original material.

“It’s a mystery why they covered it up,” Eide said.

The cornerstone to Presentation Hall was laid July 28, 1938 — exactly 80 years ago. The venue opened March, 8, 1939. Funding and the land for the project were provided by Charles H. Mayo and Mayo Properties Association as a gift to the city. Mayo personally contributed $150,000 toward the project.

The gift came during the Great Depression. Charles Mayo and William J. Mayo stated at the time the project would help create jobs and establish a world-class venue for Rochester and visitors to the city.

The foyer outside the hall has been renamed the Mayo Family Foyer and will feature artifacts from past events at Presentation Hall and a tribute to the Mayo legacy and contributions. Two nearby boardrooms have been renamed the Edith Graham Mayo Boardroom and the Hattie Damon Mayo Boardroom. Edith Graham Mayo was wife of Charles Mayo. Hattie Damon Mayo was the wife of William Mayo.

“I’ve longed for that history and connection here,” said Donna Drews, executive director of the Mayo Civic Center. “I think as we added blocks to the civic center, some of that was lost.”

Work on the restoration is expected to wrap up in August. A dedication is planned for Sept. 10.

Now that the 80-year-old facade is back in the light, Matt Dacy, director of Heritage Hall, the Mayo Clinic museum, and Eide expect it to last another 80 years and more.

“They invested in long-lasting material,” Dacy said. “It would be cost-prohibitive to try to duplicate this today.”