Gordon Felt knew his brother was sitting directly in front of two of the terrorists who hijacked United Airlines Flight 93.

But it "never really hit me," Felt said, until he walked through the new, immersive visitor center at the Flight 93 National Memorial. There it was, the seating chart with his sibling's name on it: Edward Felt, first class, second row.

"It kind of came crashing back," said Felt, whose brother took part in a passenger revolt that brought the plane down in a southwestern Pennsylvania field. "Those feelings that were always there — the emotion, the anger, the sense of loss — really are drawn back to the surface."

Sitting on a hill overlooking the crash site near Shanksville, the $26 million visitor center complex will be dedicated and opened to the public on Thursday, one day before the annual 9/11 observances in Pennsylvania, New York and Washington. Victims' family members got a private tour on Wednesday.

Fourteen years in the making, the center uses photos, video, artifacts and interactive displays to tell the story of Flight 93, the only jetliner among the four commandeered by terrorists that failed to reach its intended target on Sept. 11, 2001. Two planes crashed into the World Trade Center towers in New York and one slammed into the Pentagon outside Washington. More than 3,000 people died.

The center's 10 exhibits are laid out chronologically, with visitors learning how the 33 passengers and seven crew members — at least some of them already aware the nation was under attack — voted to charge the cockpit and then fought to regain control of the plane, whose hijackers are believed to have wanted to crash it into the U.S. Capitol.

"You are seeing an incredible story of heroism, a piece of American history playing out in front of you as you are walking through this exhibit that gives perspective on the day," said Felt, president of Families of Flight 93.

One video traces the aircraft's erratic movements in real time, fading to black at the moment of impact. Bits and pieces of the debris field are displayed under glass.

Picking up a handset, visitors can listen to recordings of the voice messages that two passengers and a flight attendant left for family members minutes before plane went down.

"I'm on United 93 and it's been hijacked by terrorists who say they have a bomb," passenger Linda Gronlund, calling her sister Elsa, begins matter-of-factly. "Apparently they have flown a couple of planes into the World Trade Center already and it looks like they're going to take this one down as well."

She breaks down sobbing: "Mostly I just wanted to say I love you and I'm going to miss you."

Other displays trace the recovery and investigation.

The center's stark, 40-foot exterior concrete walls are split by a black granite walkway that marks the doomed plane's flight path. Visitors are led through the exhibits to an outdoor platform that offers a commanding view of the crash site and surrounding hills.

Debby Borza, whose daughter, Deora Bodley, 20, was one of the youngest passengers aboard Flight 93, said she hopes the visitor center will inspire.

"The view I come from now is what's available for the visitors, the difference that it'll make in their lives, the courage that they'll find, the fortitude," she said after touring the site. "They'll be moved to take on things that they may have thought were only a dream in their lives."

The money for the visitor center complex was raised from 120,000 private donors, along with contributions from the state and the federal government. Officials project attendance will rise from 300,000 per year to around 500,000.

Development of the Flight 93 National Memorial is nearly complete, with only the planned Tower of Voices, a 93-foot structure with 40 wind chimes, still to be built.