Nation marks 21st anniversary of 9/11 attacks

(CNN) - On Sunday, the nation marked the 21st anniversary of the 9/11 terrorist attacks by honoring the nearly 3,000 lives lost on that tragic day.

A moment of silence in New York City on a somber Sunday, 21 years after the September 11th terrorist attacks.

When Al Quaeda hijackers flew airliners into the Twin Towers, the Pentagon, and a field near Shanksville, Pennsylvania, killing nearly three-thousand people.

At the September 11th Memorial in New York City, family and friends read the names of their loved ones.

While at the Pentagon, President Joe Biden attended a wreath laying ceremony where he paid tribute to those killed there.

"This is a day not only to remember, but a day of renewal and resolve for each and every American. Our devotion to this country to the principle imbodies to our democracy , that is who we owe those we remember today."

Biden also referenced the drone strike which killed Ayman Al-Zawahiri earlier this year, saying the Al Qaeda terrorist leader would never threaten the American People again.

The President also shared what he sees as the greatest lesson learned from 9/11.

"We regained a light by reaching out to one another, and finding something all too rare, a true sense of national unity, to me that's the greatest lesson of September 11th."

On the anniversary of a day, we will never forget.