Sometimes the simplest memorials are the most moving.

Lawrence T. Stack, an FDNY commander in charge of a safety battalion that investigated on-duty deaths, died on Sept. 11, 2001 when the north tower of the World Trade Center collapsed.

Long Island Newsday reports that Stack, a 33-year veteran, had been pinned under rubble when the south tower fell, but had broken free and continued rescue efforts. According to eyewitness accounts, he and another fire chief were rescuing a man who had severed his Achilles tendon when the second tower fell, killing all three men.

In this photo, posted to Reddit on the 11th anniversary of the attacks, a simple message of remembrance marks a beam high atop One World Trade Center.

The message reads: "In memory of Lawrence T. Stack, FDNY Chief, Battalion 50."

The effect was not lost on members of the social news community, who commented on the memorial's fittingness.

"It'd be cool if they had done [that] for every I-Beam and support -- write a bunch of names in so that the building itself is made up, symbolically, of those that died on that site on 9/11," user "WhatamIwaitingfor" wrote. "A phoenix from the ashes."

In August, a steel beam with a signature and message from President Barack Obama and the first lady, as well as signatures of police officers and construction workers, was lifted into place at the top of the 104-story building. In 2006, families of 9/11 victims signed a beam at the base of the tower, the New York Times reports.

Also on HuffPost:

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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)