On Wednesday (Sept. 11), celebrities online paid tribute to the victims of 9/11 on the 23rd anniversary of the devastating 2001 U.S. terrorist attacks, which claimed the lives of 2,977 people and affected their families forever.

In New York City, a ceremony was held to mark the anniversary of the attacks, with many gathering to pay their respect to those who lost their lives in the attacks, including the firefighters and police officers who came to aid that day.

The ceremony began at 8:46AM with a moment of silence to mark the time the first plane crashed into the North Tower of the World Trade Center.  Current vice president Kamala Harris and former President Donald Trump, who gave a heated presidential debate just last night, showed a rare moment of unity when they shook hands.

Others in attendance included J.D. Vance, Rudy Giuliani and Michael Bloomberg.

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On social media, several other stars, including athletes, politicians and political figures, shared personal posts in remembrance of 9/11 and its victims.

On Instagram, Katie Couric recounted the day in great detail.

"The day the sky was a bright, cerulean blue. The day 2,977 souls perished. The day dreams were extinguished. The day medical professionals mobilized and waited in hospitals across the city but no one came. The day New Yorkers walked around in a daze and the nation, in fact the world, was in a state of shock. The day the nightmare began for so many families. The day we as a country became united in the face of unspeakable evil. The day I will never forget," she wrote.

Former president Barack Obama posted a tribute on Twitter honoring those who lost their lives in the attacks.

"Today we honor the memory of all those we lost on September 11, 2001. May we never forget their stories – and the bravery of our first responders and troops who sacrificed so much," he shared.

Check out more celebrity tributes on the anniversary of 9/11, below.

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Gallery Credit: Chris Compendio

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