Discovery, History Channel and Channel 21 in New York will air 9/11 TV specials today to commemorate the attacks.

Discovery will show today the TV special "The 9/11 Surfer" at 8 p.m. in which survivor Pasquale Buzzelli tells NBC's Willie Geist how he was on a 22nd floor stairwell on the North Tower when it collapsed.

History channel will start airing 9/11 specials starting at 4 p.m. today with "Voices From Inside the Towers," a special that uses audio records, such as recorded phone calls from people inside the buildings--some of whom perished and some who survived--as they contacted family members, friends, 911 dispatchers to provide a chillingly clear mental picture.  "The Days After," airs at 6 p.m. "Hotel Ground Zero," will air at 8 p.m. Is the story from the 940 tourists, visitors and staff in the Marriott WTC Hotel, located beneath and between the Twin Towers, who found themselves at the epicenter of the disaster. "102 Minutes That Changed America" and "The Man Who Predicted 9/11" about the 62-year-old head of security at the Morgan Stanley Bank in the South Tower who predicted the attacks will air at 9p.m. and 11 p.m. respectively. (All times EST.)

Also today, Channel 21 will show "Metal of Honor: The Ironworkers of 9/11" at 7 p.m.

Tuesday marks the 11th anniversary of the attacks where nearly 3,000 people were killed. President Barack Obama and First Lady Michelle Obama marked the anniversary today observing a moment of silence on the White House and the President delivered a speech at the Pentagon.

"Instead of changing who we are, the attacks have brought out the best in the American people," Obama said in his weekly address. "Instead of turning on each other, we've resisted the temptation to give in to mistrust and suspicion."

Separately, the 9/11 ceremony at the World Trade Center in New York City where families of the 2001 and 1993 attacks' victims were expected to attend, took place starting at 8:40 a.m. EST. Moments of silence would continue throughout the morning until the ceremony concludes at 12:30 pm.

Celebrities also joined the nation honoring the lives lost on 9/11 through Twitter.

"My heart remains heavy for the victims & the families of those we lost on 9/11. As a city & a nation we are forever changed. #Honor911," Katie Couric, TV host of 'Katie'wrote on her Twitter this morning.

"On another clear blue morning, thoughts with the families & friends of those killed on 9/11," actress Mia Farrow posted on Twitter today.

"I say vics of 9/11 are heroes b/c they were ordinary ppl just trying to live. Their sacrifice will always be sadly heroic. #NeverAgain!!!" actress Octavia Spencer wrote on Twitter.

Singer Wyclef Jean wrote:

"To the families of 9 11 and all the families of the world that are suffering from lost of love ones may God give u strength to carry on!"

Olympic Medallist Michael Phelps also offered a prayer for the victims.

"Thoughts and prayers for those who lost loved ones...#911 #NeverForget"

Discovery's "The 9/11 Surfer" Watch Clip Below:

Tags: tv shows