One week before the first anniversary of the Sept. 11 terrorist attacks, Paul Swenson happened to glance at a newspaper somebody was reading on his flight from Northern California to Salt Lake City. A number jumped out at him: 3,031. At the time, it was the estimated number of people believed to have died that awful day in 2001.

Swenson, owner of Colonial Flag, a flag supply company in Sandy, Utah, couldn't get the number out of his mind. Somehow, he told himself, “I need to figure out a way to bring that number home.” That night, he came up with a plan, which he presented to Sandy city officials the next morning. He wanted to donate 3,031 American flags for a “healing field” on a grassy promenade in front of City Hall. Everyone agreed, and Swenson quickly lined up volunteers to help him set up the flags the night before the first anniversary of the terrorist attacks.

At 3 a.m., as he stood alone in the field, watching the flags fluttering in the moonlight, Swenson noticed a woman slowly walking up and down each row, hugging the flags.

“I knew then that the healing field would show more than the magnitude of 9/11,” he told The Washington Post. “It would become a personal experience for every person who visited.”

Sixteen years since that first flag display, his idea has taken off with hundreds of cities and organizations nationwide.

“You can see the power of the field when you watch people touch the flags,” said Swenson, now 62 and chairman of the Colonial Flag Foundation, a nonprofit that helps cities and community groups nationwide create “healing fields” of their own for Patriot Day, Memorial Day, Veterans Day and the Fourth of July.

“When people walk through a field and realize that each flag represents somebody’s husband, wife, child, uncle, aunt or neighbor, it shows the enormity more than a number on a page,” he said. “It has a huge emotional impact.”

Today, on the 17th anniversary of the terrorist attacks on the Pentagon and the World Trade Center that killed 2,996 people, more than 60 communities will host healing fields with help from Swenson’s foundation.

Colonial Flag sells flags to cities and organizations at cost — $15 each — to use year after year or auction off to the public to benefit local charities.

Swenson, who doesn’t take a salary as chairman of the foundation’s board, said Colonial Flag earns enough money to pay three employees to run the foundation and generally breaks even.

Swenson started his flag business a few years after college. The Vietnam War had just ended when Swenson graduated from Salt Lake County’s Skyline High School in 1974 and enrolled as a political-science major at the University of Utah. Five years later, he said, he decided to go into the flag business, selling American flags, international flags, sports flags and flagpoles with his brother, David, eventually buying the entire company with his wife, Elizabeth, in 1989.

Swenson said he always described himself as patriotic, but seeing more than 3,000 flags at that first healing field in his hometown “brought it all home.”

“You could see the emotion on everybody’s faces,” he said.

Within days, he said, other cities started calling, hoping to host similar events the following year.

“After four years, my wife and I were at a point when we wondered if we could keep doing it,” said Swenson, “because we had spent more than half a million of our money doing healing fields.”

That was when he switched from donating the flags to selling them at a low cost.

“I can’t imagine not doing this now,” he said. “I can think of no better way to honor those who died on that horrible day than with a healing field.”

Cities and towns across the country now commemorate the dark events of 9/11 with a field of flags.

"Each year, our healing field brings people from all walks of life to heal what hurts their hearts,” said Kevin Brady, executive director of the Greater Huntington Park & Recreation District in Huntington, W.Va.

This is the seventh year in which Brady’s city has set up more than 3,000 American flags in Spring Hill Cemetery in honor of those who lost their lives in the 2001 attacks. A local doctor, Paul Ambrose, was among those killed when the plane he was on — American Airlines Flight 77 — crashed into the Pentagon. Brady helped coordinate a fundraiser on the 10th anniversary of 9/11, giving people the chance to buy flags from the display and contribute to building a bell tower in the cemetery.

“With Paul Swenson’s help, we created a tradition in our community that will never be eliminated,” Brady said. “Each year, I think I’ll make it through our ceremony without tears, and each year, as the tears flow down my face, I’m reminded of the commitment we all made as Americans: that we will never forget,” he said.

After putting up his first healing field in Sandy in 2002, Swenson initially wondered if he could summon the energy and commitment to make it an annual event. More than 200,000 people had come to see the flags that first year. Several weeks later, overwhelmed with a desire to personally visit the sites of the terrorist attacks, he said, he flew to Virginia, rented a car and drove to the Pentagon early in the morning to pay his respects.

After watching construction crews work for more than an hour, Swenson drove on to Shanksville, Pa., where United Airlines Flight 93 went down in a field after passengers intervened to keep hijackers from steering the plane toward the U.S. Capitol. From Pennsylvania, he went on to Ground Zero in Lower Manhattan, arriving at 2 a.m., he recalled, to watch reconstruction efforts underway in the footprints of the twin towers, before catching a flight back to Salt Lake City.

“It was an emotional trip,” Swenson said, “and I knew then that I needed to keep going with it. A lot of towns across the country had heard about our field and wanted to do healing fields of their own.”

With help from his sister, Sawn, he set up the foundation. Fifteen years later, he and his sister have helped organize more than 800 healing fields, from Hawaii to Massachusetts, along with “fields of honor” for living war veterans.

“Seeing all those flags lined up in one space is a powerful thing,” said Sawn Swenson, 64, who is the foundation’s national director. A former Delta flight attendant, she attended the first anniversary commemoration of 9/11 at Ground Zero, then flew home to Utah to see her brother’s healing field.

“It was like the spirit of the people who died at Ground Zero followed me home,” she said. “As I stood in the field that evening, a breeze picked up and all those flags started flying. It changed my whole world. I really felt that Paul had been inspired.”

On the 10th anniversary of 9/11, she and her brother helped organize a healing field at the Pentagon, setting up more than 3,000 flags in a parking lot. Friends and relatives of the 184 people killed at the Pentagon were among those who showed up to help put the exhibit together.

To commemorate the 17th anniversary of 9/11, Paul Swenson said he planned to go to one of the 60 healing fields he helped organize, then quietly observe the impact.

“The field comes to life when you’re out there walking in those rows and rows of flags,” he said. “It’s an incredible feeling.”