These photos, video of the Pentagon on 9/11 anniversary will move you; So many tears

Lori Ziganto | 4:39 PM on September 11, 2014

A large American flag was unfurled at the Pentagon this morning to commemorate 9/11.

Why the military unfurls a giant U.S. flag down the side of the Pentagon on Sept. 11 http://t.co/R2lqx53WXC via @washingtonpost

— Laughter's Good (@Collmaxw) September 11, 2014

A little history: Here is why it is done:

At the Pentagon, the crash shook the building so hard that many inside wondered if there had been an earthquake. One hundred eight-four people were killed, ranging from Army Lt. Gen. Timothy J. Maude to rank-and-file service members and civilians working in the building.

As this Defense Department account recalls, the military unfurled a massive flag down the side of the building, just to the right of where the wreckage of the crash smoldered. Army Maj. Gen. Jim Jackson, commanding general at the time of the Military District of Washington, called for one at nearby Fort Myer, Va., and the U.S. Army Band sent a garrison flag — the largest authorized in the military, at about 20 feet by 38 feet.

The flag flew for one month, but the Pentagon has continued the tradition.

And a touching and moving tradition it is.

A large American flag has been unfurled at the Pentagon to honor the victims and survivors of the 9/11 attack. pic.twitter.com/MonPrnLk70

— Megan McGrath (@MeganMcGrath4) September 11, 2014

American flag dropped from #Pentagon roof on same side that was struck 13 years ago, #Sept11 '14 (via @nbcwashington) pic.twitter.com/YgVpC8BrMN

— Jon Street (@JonStreet) September 11, 2014

Flag draped over Pentagon in Washington DC on this the 13th anniversary of that tragic day. pic.twitter.com/0f17Q5yEIB

— Hoss Communications (@MikeHossComm) September 11, 2014