Today marks the 10th anniversary of the September 11 attacks -- and many celebrities have taken to Twitter to remember the victims and their families.
Anderson Cooper: "On the air right now at the world trade site. Families of those killed are gathering. It is a beautiful memorial."
Lea Michele: "To all the families and people of New York affected by the tragedies of September 11th my thoughts and prayers go out to you."
Demi Moore: "Today on #9/11 as we take pause to honor and remember the loss let's us also connect and hold the love that heals and unites us!"
Rob Lowe: "Today, I remember. Today, I promise I will never forget. Never."
Alyssa Milano: "NeverForget."
Elisabeth Hasselbeck: "When you move today, move in tribute. Wear red to remember. #remember #movingtribute#neverforget. If u see a group running in red- join us."
DJ Pauly D: "Take A Moment And Pray For Those Who Lost Their Lives, Their Loved Ones, And The Heroes That Risk They're Lives To Keep Us Safe."
Lil Wayne: "Remembering those we lost on this unforgettable day. God bless their families and may their souls rest in peace."
Wilmer Valderrama: "On this September 11.. Let's remember it as the day we all stood united as one nation under god.. Tall and defiant against the face of evil."
Olivia Wilde: "10 years ago today, our shocked world marched together for Peace. let's not forget that spirit. my heart goes out to all who have suffered."
Carson Daly: "GodBlessAmerica."