Re-watching footage from 9/11, regardless of the anniversary, is undoubtedly eerie, but for some, remembering that terrible day is often necessary in order to pay tribute to those who lost their lives.

For others, especially a generation growing up in the post-9/11 world, watching the footage helps form at least a partial understanding of the attacks.

Technology was able to preserve the memory of the events, for better or worse. Now, the clips that were once only considered a dramatic memory of a tragic day have become a part of history.

The availability of video cameras and recording devices at the time made 9/11 possibly the most recorded tragedy in national history. Though 2001 pre-dates the widespread use of smartphones and cell phone cameras, there were many New Yorkers, and Americans in general for that matter, within arms-reach of a camcorder.

However, there is still little footage of the first plane flying into the North Tower of the World Trade Center, since few eyes were on the sky until it happened. There is also no footage of the plane crashing in Pennsylvania (the most widely seen footage is from after the crash), and there's little coverage of the crash at the Pentagon.

But the moment the second tower was hit is well documented. As many Manhattanites focused their cameras on the first tower burning, they witnessed United Airlines Flight 175 fly into the South Tower. The reactions, as can be heard in many of the videos below, were dramatic.

When the towers began to fall nearly an hour later, many had long been filming the incident, and news cameras were all over the scene.

With all eyes on New York -- a city that has long housed national media titans such as CNN, ABC, NBC and Fox News -- millions of Americans were exposed to the attacks in near real time. From impact to collapse, it was all captured and, for the most part, shown live on television sets throughout the country, and perhaps the world.

The coverage was so in-depth that sites such as the Internet Archive have collected enough footage to virtually replay the day.

We've also provided a number of videos from 9/11, which can be seen below.

WARNING: Some of the language in the videos below may not be suitable for all ages.

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  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The Pennsylvania Crash Site

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The Pentagon

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

  • 9/11 Video: The World Trade Center

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  • U.S Senators Kirsten Gillibrand, and Charles Schumer, D-NY, place American flags in names engraved in the border of one of the World Trade Center Memorial reflecting pools, during the 11th anniversary observance, in New York, Tuesday Sept. 11, 2012. (AP Photo/Justin Lane, Pool)

  • A man embraces a woman as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • An American flag flies over a man pausing near a reflecting pool at the National September 11 Memorial during the observance of the 11th anniversary of September 11 in New York, on Tuesday, Sept. 11, 2012. (AP Photo/Todd Maisel, Pool, New York Daily News)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012.(AP Photo/Jason DeCrow)

  • A firefighter's hat rests on names of firefighters at the south reflecting pool who died in the attacks at the World Trade Center, during the 11th anniversary observance at the World Trade Center Memorial, in New York, Tuesday Sept. 11, 2012. (AP Photo/Justin Lane. Pool, EPA)

  • A woman holds a young boy as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • A woman becomes emotional while holding a photo of her father after reading his name as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • A boy observes a moment of silence as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • New Jersey Governor Chris Christie, left, places a flag on a memorial site as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/The Daily News, Todd Maisel, Pool)

  • Amelia Tedesco of Staten Island, N.Y. touches the name of her son-in-law Walter Baran of Staten Island, N.Y. during observances held on the eleventh anniversary of the attacks on the World Trade Center, at the site in New York, September 11, 2012. Baran was killed on the 90th floor of the south tower during the attacks. (AP Photo/Craig Ruttle, Pool, Newsday)

  • A young boy scratches the name on paper as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/The Daily News, Todd Maisel, Pool)

  • Two girls scratch names on paper as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/The Daily News, Todd Maisel, Pool)

  • Family members of Belinda Pascua Domingo of New York place mementos on her name during observances held on the eleventh anniversary of the attacks on the World Trade Center, at the site in New York, September 11, 2012. (AP Photo/Craig Ruttle, Newsday, Pool)

  • September 11 POOL image from New York

    Captain John Lam rolls up an etching of his uncle Stuart Louis on the South Tower pool wall at the National September 11 Memorial, for his aunt during observances on the eleventh anniversary of the attacks on the World Trade Center, Tuesday. Sept. 11, 2012 in New York. (AP Photo/Timothy A. Clary, Pool)

  • Nina Fisher, Mia Tinson

    Nina Fisher, sister of 9/11 victim Andrew Fisher, embraces her niece Mia Tinson, 9, at ceremonies marking the eleventh anniversary of the terrorist attacks at the World Trade Center, Tuesday, Sept. 11, 2012 in New York. Begum, who is from Bangladesh, lost her nephew, Nural Miah and his wife Shakila Yasmin, two of the many Muslims who also died the attacks. New York City is observing the eleventh anniversary of the September 11, 2001 attacks. (AP Photo/John Moore, Pool

  • Tina Grazioso, left, looks at the name of her husband, John Grazioso, at the World Trade Center Memorial, who died in the attacks at the World Trade Center, during the 11th anniversary observance, in New York, Tuesday Sep. 11, 2012. At right is John Grazioso's sister Carolee Azzarello. (AP Photo/John Moore, Getty Images, Pool)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012.(AP Photo/Jason DeCrow)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • Childhood friends from Italy, Lucrezia Susca, 78, left, and Chiara Pesce, 75, center, hold photos of their grandchildren Grace Gollante-Susca and Danny Pesce, who were also friends and died together while working at Cantor Fitzgerald, as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • New York Governor Andrew Cuomo, kneeling left, and New Jersey Governor Chris Christie, right, speak with Miah Afsaruddin at ceremonies for the eleventh anniversary of the attacks at the World Trade Center, in New York,Tuesday Sept. 11, 2012. Afsaruddin, from Bangladesh, lost his son Nural Miah and daughter-in-law Shakila Yasmin in the 9/11 attacks. (AP Photo/John Moore,Getty Images, POOL)

  • Former New York Mayor Rudolph Giuliani, far left, New York Mayor Michael Bloomberg, fifth left, New York Governor Andrew Cuomo, fourth right, and New Jersey Governor Chris Christie, second right, attend as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • The World Trade Center Flag is presented as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • A woman becomes emotional after reading the name of her father as friends and relatives of the victims of 9/11 gather for a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site, Tuesday, Sept. 11, 2012, in New York. (AP Photo/Jason DeCrow)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center attend a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Mark Lennihan)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks, look over a reflecting pool during a ceremony at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012.(AP Photo/Mark Lennihan)

  • Friends and families of victims of the Sept. 11, 2001, terror attacks, look over a reflecting pool during a ceremony at the National September 11 Memorial, Tuesday, Sept. 11, 2012 in New York. As in past years, thousands are expected to gather at the World Trade Center site in New York, the Pentagon and Shanksville, Pennsylvania, to read the names of nearly 3,000 victims killed in the worst terror attack in U.S. history. (AP Photo/Mark Lennihan)

  • A man paces a bouquet of flowers at a reflecting pool during a ceremony at the National September 11 Memorial, Tuesday, Sept. 11, 2012 in New York. As in past years, thousands are expected to gather at the World Trade Center site in New York, the Pentagon and Shanksville, Pennsylvania, to read the names of nearly 3,000 victims killed in the worst terror attack in U.S. history. (AP Photo/Mark Lennihan)

  • Maria Rodriguez sits with photos of her son-in-law Emilio Ortiz as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center gather for a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center gather for a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • Friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center gather for a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • A firefighter makes a rubbing of a victim's name as friends and relatives of the victims of the Sept. 11 terrorist attacks on the World Trade Center gather for a ceremony marking the 11th anniversary of the attacks at the National September 11 Memorial in New York, Tuesday, Sept. 11, 2012. (AP Photo/Jason DeCrow)

  • The tower known as 1 World Trade Center, left, the National September 11 Memorial, bottom left, and 4 World Trade Center, right, are bathed in light, Tuesday, Sept. 11, 2012 in New York. Tuesday is the eleventh anniversary of the terrorist attacks of Sept. 11, 2001. (AP Photo/Mark Lennihan)

  • Photos of victims of the attacks of September 11 and messages from their loved ones, are shown at a news conference, Monday, Sept. 10, 2012 in New York. On the eve of the Sept. 11 anniversary, the faces and recorded voices of those who died have been unveiled as part of the future 9/11 Memorial Museum. (AP Photo/Mark Lennihan)