It's been 16 years since Al-Qaeda terrorists hijacked American Airlines Flight 77 and crashed the aircraft into the Pentagon during the 9/11 terror attacks.
The tragedy took place on September 11, 2001, at approximately 9:37 am in Arlington County, Virginia, following a horrific attack on the World Trade Center in New York City.
The FBI recently publicized a devastating unseen batch of archival photos on its website that show the damage to the Pentagon hours after the attack, ABC News reports.
The photos -- which have been kept secret until now -- can be found on the FBI's website under the "FBI Records: The Vault" section.
First responders are pictured in a majority of the photos trying to keep the roaring blaze under control.
Other photos show the Pentagon's damaged interior and exterior after being scorched by the plane crash, including a gaping hole left where the American Airlines plane made contact with the building.
The hole is reportedly 20 ft wide and 100 ft deep.
Fragments of the plane can also be spotted in the harrowing photos after the aircraft barreled into the building.
The flight departed Dulles International Airport and was headed to Los Angeles -- but it was taken over by five Al-Qaeda hijackers mid-flight.
Hijackers crashed the plane into the Pentagon -- which serves as the headquarters of the Department of Defense -- at 9:37 am.
During the attack, a total of 189 people died, including 125 people who worked inside the building.
However, it's been reported the death toll would have been significantly higher if the plane hit a more populated section of the building.
The plane struck between the first and second floor of the Pentagon in an area that was relatively empty due to construction.
Regardless of what side of the building Flight 77 struck, the terror attack was a horrific one that we will always remember, and the new photos are a sobering reminder of that tragic day in American history.