SHANKSVILLE, Pa. » The families of the passengers and crew aboard United Flight 93 recalled their loved ones as heroes who made history with unselfish and quick actions.

"In a period of 22 minutes, our loved ones made history," said Gordon Felt, the president of the Families of Flight 93, whose brother, Edward, was among the 33 passengers and seven crew members aboard the hijacked plane on Sept. 11, 2001.

Families of those aboard the plane, along with nearly 200 more people, read the names aloud and bells tolled, as they marked the 12th anniversary of the Sept. 11 attacks.

Flight 93 was traveling from Newark, N.J., to San Francisco when it was hijacked with the likely goal of crashing it into the White House or Capitol.

As passenger Todd Beamer issued the rallying cry "Let’s roll," he and several fellow passengers rushed down the airliner’s aisle to try to overwhelm the hijackers after learning of the coordinated attacks on the World Trade Center and the Pentagon.

The 9/11 Commission concluded that the hijackers downed the plane as the hostages revolted.

As the names were read, a light haze began to burn off the surrounding hills. The memorial wall of white stone has each victim’s name engraved on a separate panel, and the scene was framed by yellow wildflowers behind the stones.

U.S. Interior Secretary Sally Jewell recalled the sacrifice the passengers made.

"We never know when we’ll be called to lay down our lives for others," she said, speaking of the bravery of passengers and crew who fought back against the hijackers.

The reading of names and tolling of bells was the first part of the Flight 93 National Memorial’s plans to honor the victims of the Sept. 11 attacks.

Later today, park rangers and volunteers will give presentations about Flight 93 and the creation of the memorial park, which is located in Shanksville, about 75 miles southeast of Pittsburgh.

A groundbreaking for a 6,800-square-foot visitor center was held Tuesday. The building will be broken in two at the point of the plane’s flight path overhead. It is expected to open in late 2015.

The first features of the memorial in Shanksville were completed and dedicated in September 2011, including new roads and a Memorial Plaza near the crash site. Forty memorial groves of trees have also been planted, and large sections of the park have been replanted or reforested.

The tale of the courageous actions of everyday people aboard Flight 93 helped provide a measure of optimism for the American public in the dark days and weeks that followed the terrorist attacks.

It also inspired a 2006 docudrama, "United 93," the first big-screen dramatization about the terrorist attacks that used a cast of unknown actors and played out roughly in real time from the passenger check-in to the crash.

Visitors to the park have left more than 35,000 tributes at the site, and they have been collected as part of an archival collection.

Online:

Flight 93 National Memorial: http://www.nps.gov/flni