Ten years ago, what began as a calm, peaceful morning on Sept. 11, 2001, turned into a pivotal moment that would shake the security of America and the world. United Airlines Flight 93 began its journey from Newark, N.J., to San Francisco, Calif. Forty-six minutes into the flight, four terrorists took control of the aircraft. During the hijacking, many passengers were able to call loved ones who informed them of the attacks on the World Trade Center and the Pentagon.

Realizing that the terrorists had rerouted the plane to Washington, D.C., and knowing they were the only ones who could stop this attack, the passengers took action. The skies above a small, Pennsylvania town became the first battleground in the war against terrorism. During the passengers’ attempt to retake control, Flight 93 crashed into a field in Shanksville, a rural town southeast of Pittsburgh.

Forty people lost their lives on Flight 93, but their families, loved ones, and many others would see that their sacrifices would always be remembered. Shortly after the tragedy, a permanent memorial was planned for the site. The National Park Service (NPS) was assigned as the lead agency, and the NPS tapped the U.S. Army Corps of Engineers to manage the first phase of construction, which represented $16 million of the estimated $60 million memorial.

The Pittsburgh District managed the construction, and after nearly two years of development, the Flight 93 National Memorial was dedicated Sept. 10-11, 2011. The partnership between the district and the NPS was vital to ensuring the first of three construction phases was completed before the dedication ceremony, said Bryan Ciccocioppo. He and Sara Hillegas comprised the construction management team for the memorial.

“The Corps of Engineers was essential in facilitating the permits necessary to begin the construction of the memorial, said Keith Newlin, the NPS’ general superintendent of western Pennsylvania parks. “Their assistance allowed the construction to begin and finish on schedule. As a partner, they brought their expertise and worked with all of the partners to build this memorial on schedule.”

Phase 1 entailed grading the site and building the visitor pavilion, walkways, family parking lot, and the Flight Path Wall. The next two phases include tree plantings and construction of a visitor center.

Officials broke ground on the site in late 2009 and construction began in late March 2010. The design required the massive relocation of nearly 500,000 cubic yards of soil. The memorial architect, Paul Murdoch of Los Angeles, moved that soil to create a “bowl” that slopes down to and focuses visitors on the Memorial Wall.

“The topography was always part of the design,” Murdoch said. “We reworked the area to get the slope.” The rearrangement of the landscape required the design and installation of a stormwater draining system, to keep water away from visitor areas.

Due to the amount of construction, the district’s Regulatory Branch had to assist with the permit to allow the installation of four new wetlands to replace the ones that were disturbed or destroyed.

“With a site this large, there was a lot of work involved in the permitting process for our regulatory office,” Ciccocioppo said. “But we have a good team and they walked the entire site to make sure everything was done right. The regulatory work was phenomenal.”

According to Murdoch, there were concerns about the weather.

“A lot of the parts of the memorial were designed to be prefabricated off site. This was done so that work could continue during the winter,” he said.

The items fabricated off site include the precast concrete for the Memorial Wall and the marble work for the Flight Path Wall. Other items include the raised precast concrete platforms and the wooden benches that set on top of them.

Once visitors travel down the road and arrive at the memorial, they will enter through a visitor’s shelter. The shelter is built of concrete that was formed to look like hand-hewn hemlock wood to signify that Flight 93 crashed in a hemlock grove. The same concrete pattern lines the back side of the concrete wall along the walkway to the Flight Path Wall where the names of the 40 heroes are inscribed.

The focal point of the memorial is the Flight Path Wall, which is made of Vermont Danby white marble.

“The recognition of all 40 names is important,” Murdoch said. “We used the same kind of stone for all the slabs, but each individual has their own slab and each slab is unique.”

In front of the wall, visitors will travel along granite paving stones that follow the path of the airplane as it crashed into the field.

Funding for the memorial was raised by Flight 93 families and the National Park Foundation’s Flight 93 National Memorial Campaign.

“There is a lot of significance to the completion of the first phase, but we still have a lot of work to do,” Murdoch said.

The next part of the project includes planting 1,600 trees, 40 for each of the people on Flight 93. The tree planting began July 30. A visitor center will also be built at the site. The work is set to begin in 2012 and be completed in 2014.

Visitors are able to access the site from Route 30 on a new road that was constructed.

“You see the road and the wall and sometimes you forget about the effort that went into building this memorial. Sometimes, when you stop and think about what you’re working on, it can be difficult,” Ciccocioppo said, referring to the sacrifices made by the passengers of Flight 93 and their families.

“The rest of the project is important because it is all part of the memorial experience,” Murdoch said. “It’s always going to be special when you come here.”

This article first appeared in the 2011-2012 edition of the U.S. Army Corps of Engineers: Building Strong®, Serving the Nation and the Armed Forces publication.