It has been 12 years since the 9/11 tragedy that took away thousands of lives. Commemorating the 12th anniversary of the 9/11 attacks, people from across the globe paid respect in their own ways. Celebrities were not behind as they honoured the brave souls via Twitter.

Here is a collection of tweets that touched our hearts. Read on.

"Let's all take a moment today to remember 9/11...Never forget," Lauren Conrad tweeted.

"Do a good deed today in observance of @911day. Make your pledge at http://911day.org . #911day," Miley Cyrus expressed her feeling via this tweet.

"12 years ago today Sept 11th. We Will Never Forget. Still remember the smoke in the sky. Saying lots of prayers for families who lost lives," Lady Gaga tweeted.

P. Diddy got really emotional and gave a tweet-salute to the heroes. He tweeted, "Our Heroes! United We Stand as we Remember 9-11.″

"Glad to be in NY on 9/11. Remembering all those who lost someone," Ben Stiller tweeted.

"Never forget those whose lives perished on 9/11. God bless our country," singer Sheryl Crow tweeted.

"Thinking about the family's who lost loved ones and those who were affected by 9/11 ❤ #lmemorial #love," Doutzen Kroes of Victoria's Secret Angel tweeted.

Andy Cohen reminded us that we must never forget. "#NeverForget #NeverForget #NeverForget #NeverForget #NeverForget #NeverForget."

"No Hate today. Lets all remember the lives lost on 9/11. You will NEVER be forgotten. RIP❤ #heros," Snooki tweeted.

"Big Bang Theory's" Kaley Cucuo posted three tweets with Instagram photographs.

"#neverforget #9/11."

"#neverforget forever standing tall! #9/11."

"Another person I will never ever forget :) #9/11," Kaley also remembered actor John Ritter's by posting his picture in Instagram account.

"9/11 I was working on a film on Roosevelt Island minutes away from the towers we watched speechless, Unbelievable #NeverForget," actor Jamie Hector tweeted.

"half-mast 12 years later #nyc #grateful #9/11,″ Jennie Garth tweeted.

"Remembering the Fallen on 9/11,″ Bret Michaels tweeted.

"9-11. All I could remember was seeing smoke coming up Suitland Parkway from the pentagon and praying that my Mom was ok at work," Kevin Durant remembered through this tweet.

"9/11 United We Stand," Carmelo Anthony tweeted.

Such heart-rending tweets! How are you remembering the day? Let us know by dropping a comment or a prayer for the ones who lost their lives and their families.

Check out the slideshow and remember the day.

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