STONYCREEK TOWNSHIP, Pa. (KDKA/AP) — The commemoration of the 18th anniversary of the Sept. 11 terror attacks was held Wednesday morning in New York City, Washington DC and in Stonycreek Township, Pennsylvania.

The families of the passengers and crew members of United Airlines Flight 93 gathered again near Shanksville to remember their loved ones.

READ MORE: The Search For Kodiak, The National Aviary's Steller's Sea Eagle, Continued On Sunday

WATCH: Flight 93 Memorial —

Vice President Mike Pence was among the dignitaries invited to speak at the Flight 93 National Memorial.

The Secretary of the US Department of the Interior David Bernhardt also spoke, as did family members of the victims and a historian who covered the event eighteen years ago.

“It is deeply humbling as Vice President of the United States to stand before you today at the Flight 93 National Memorial,” said Vice President Pence.

The names of all the passengers were read as bells tolled for each one, and a wreath-laying ceremony was also held at the memorial wall carrying the names of the victims.

It was the first time for the gathering was held since the completion of the Flight 93 Memorial, a fact not lost on Gordy Fell, the President of the Families of Flight 93.

“School groups, veterans, tourists, history buffs and concerned citizens of the world continue to be drawn to the sacred ground, and for good reason,” Fell said.

The memorial marks the spot where the plane crashed in a rural area at 10:03 a.m. The San Francisco-bound plane had been diverted by the attackers toward Washington, D.C., when the passengers historically and heroically fought back.

(Photo Credit: KDKA)

“By their actions, their statements, and ultimately, their shared sacrifice, the 40 passengers and crew members of United Flight 93 should be celebrated and emulated for representing the greatest of all American values,” said Boston University Professor Mitchell Zuckoff, the keynote speaker Wednesday.

Zuckoff said, through their sacrifice, the brave people on Flight 93 offered Americans some hope.

“In their determination to save themselves, they saved countless others in the U.S. Capitol or the White House and they gave us the first glimmer of hope at a terrible moment,” he said.

READ MORE: Son Of Carnegie Mellon University President, Thomas Jahanian, Dies After Being Pulled From Monongahela River

One of the people they may have saved that morning was Vice President Pence — who was in DC as a member of the House of Representatives.

“I will always believe that I many others in our nation’s capital were able to go home that day and hug our families because of the courage and selflessness of your families, the heroes of Flight 93,” Pence said.

Bernhardt made a poignant observation and hopes America heard him loud and clear. Not only is it critical to “Never Forget” what happened on 9/11, but we need to be sure that all of the United States never forgets.

“This year, young Americans who were born after the attacks have enrolled in college where they will join many peers who have no direct memory of what transpired,” Bernhardt said.

The terrorists also flew two planes into the World Trade Center skyscrapers in New York and a fourth into the Pentagon in Arlington, Virginia.

In New York City, at Ground Zero there was a moment of silence and tolling bells.

Victims’ relatives and dignitaries gathered on the memorial plaza at the World Trade Center as the ceremony started at 8:46 a.m. Wednesday. That is the time when a hijacked plane slammed into the World Trade Center’s north tower on Sept. 11, 2001.

Then victims’ loved ones read the names of the nearly 3,000 people killed in the attack.

Pence has been to Shanksville many times — including 2017 for the 9/11 ceremony. Today, he stressed how that part of Somerset County has been transformed.

“Here, where a common field one day became a field of honor forever.”

President Donald Trump attended the observance at the Pentagon.

MORE NEWS: Curtains Up: Live Performances Return To Cultural District With Safety Precautions In Place

(TM and © Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)