Flight 93 Memorial nears completion in Pennsylvania

The Wall of Names rises at the Flight 93 National Memorial in Somerset County, Pennsylvania (AP Photo/Gene J. Puskar)

The Wall of Names rises at the Flight 93 National Memorial in Somerset County, Pennsylvania (AP Photo/Gene J. Puskar)

Construction is winding down on the final feature in the Flight 93 National Memorial in Pennsylvania’s Somerset County.

All that remains is to install an enormous, complicated set of wind chimes.

Architect Paul Murdoch, who first pitched his plan for the memorial more than 13 years ago, has been incrementally building features since then.

This final stage is dubbed the Tower of Voices — a 93-foot concrete structure that’ll be adorned with 40 chimes — for each of the passengers and crew members killed in the crash during the 9/11 attacks.

“This is probably the most challenging and the most unique piece,” Murdoch said. “Had we tried it day one, I’m not sure we could have done it.”

It has become an international project, with wind engineers from Colorado and Australia, a musician from upstate New York, and structural engineers from California and London.

They had to do complicated analyses of wind patterns to make sure the chimes would sound right, and they repeatedly returned to the drawing board to work on their motion.

Murdoch said it’s all worth it.

“What these 40 people did, I think, inspires service in a lot of us,” he said. “And I think it’s a very important place for Americans to see.”

The monument will officially open Sept. 9 — two days before the anniversary of the crash of the lone hijacked plane that didn’t hit its intended target.

It is believed the passengers and crew fought back — forcing the four terrorists to down the plane.

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