Americans on Tuesday will mark the 17th anniversary of the Sept. 11, 2001 terrorist attacks that claimed almost 3,000 lives.

President Donald Trump will attend a ceremony at the 9/11 memorial in Shanksville, Pennsylvania, near where United Airlines Flight 93 crashed after passengers retook control from the al-Qaida affiliated terrorists who had hijacked the plane.

FILE - A visitor to the Flight 93 National Memoria FILE - A visitor to the Flight 93 National Memorial pauses at the Wall of Names containing the names of the 40 passengers and crew of United Flight 93 that were killed in this field on Sept. 11, 2001, nears Shanksville, Pennsylvania, May 31, 2018. FILE - A visitor to the Flight 93 National Memorial pauses at the Wall of Names containing the names of the 40 passengers and crew of United Flight 93 that were killed in this field on Sept. 11, 2001, nears Shanksville, Pennsylvania, May 31, 2018.

In a statement Saturday, the White House declared September 7 to 9 as National Days of Prayer and Remembrance for the victim of the attacks.

“The faith of our Nation may have been tested in the avenues of New York City, on the shores of the Potomac, and in a field near Shanksville, Pennsylvania, but our strength never faltered and our resilience never wavered,” the statement said.

A woman reaches out to touch rose on one of the be FILE - A woman reaches out to touch rose on one of the benches of the Pentagon Memorial at the at the Pentagon, Sept. 11, 2014. FILE - A woman reaches out to touch rose on one of the benches of the Pentagon Memorial at the at the Pentagon, Sept. 11, 2014.

In the capital, the Pentagon will hold special services for families of those killed when a plane crashed into the building.

And in New York, hundreds of survivors and family members of those killed will gathered at Ground Zero, where the Twin Towers of the World Trade Center stood before two hijacked commercial flights brought them down. Twin beams of light will be projected into the sky to memorialize those lost in the attacks.

The hijackings were carried out by 19 hijackers affiliated with al-Qaida. The deadliest attack on American soil since Pearl Harbor in 1944, the events of Sept. 11th permanently changed America’s perception of security. The tragedy prompted George W. Bush to declare a war on terrorism and invade Afghanistan.

FILE - In this Sept. 11, 2001 photo, the twin towe FILE - In this Sept. 11, 2001 photo, the twin towers of the World Trade Center burn behind the Empire State Building in New York after terrorists crashed two planes into the towers causing both to collapse. FILE - In this Sept. 11, 2001 photo, the twin towers of the World Trade Center burn behind the Empire State Building in New York after terrorists crashed two planes into the towers causing both to collapse.

Almost two decades later, the anniversary remains a painful reminder for the families of those who died.

Mary Fetchet’s son Brad was working in the South Tower of the World Trade Center when the first plane hit.

“My son called my husband to let him know he was okay, and just to remind him that he was in the second tower,” Fetchet told VOA.

FILE -- In this Sept. 11, 2001 file photo, thick s FILE -- In this Sept. 11, 2001 file photo, thick smoke billows into the sky from the area behind the Statue of Liberty, lower left, where the World Trade Center towers stood. FILE -- In this Sept. 11, 2001 file photo, thick smoke billows into the sky from the area behind the Statue of Liberty, lower left, where the World Trade Center towers stood.

After her husband called her at work to tell her Brad was alive, Fetchet walked into an adjoining building. As she entered the room, she saw the second plane hitting the other tower on television.

“Of course I was hoping, trying to calculate where he was in the building, and if he had in fact had time between the time he called my husband to be below the line where the plane entered the building,” Fetchet said.

Fetchett went home after that, hoping for a call from her son that never came. Near the end of September, she held a memorial for Brad.

In the wake of the attacks, Fetchet organized groups of survivors and the families who lost loved ones.

“I pretty immediately realized that the families who’d lived around the country and in 90 countries abroad had challenges in accessing information. And many decisions were being made that impacted them directly,” Fetchet said.

The realization led her to create the charity Voices of September 11th, which provides services to families affected by the tragedy, such as sponsoring support groups and helping identify the remains of loved ones. The organization has also expanded to provide services to communities impacted by violence around the world.

“We’ve learned so much over the last 17 years,” Fetchet said. “There seems to be no end to the acts of terrorism and mass violence both here in the United States and abroad.”