WTC 7

Its dramatic collapse several hours after the Twin Towers fell triggered a decade of conspiracy theories.

Those who believed that the September 11 attacks on America were not carried out by Al Qaeda terrorists pointed to the fall of World Trade Center Building 7 as proof of their wild claims.

But a newly released video appears to finally prove once and for all that Building 7 was brought down by the intense heat of the blazing World Trade Center - and not explosives, as conspiracy theorists claim.

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Burning: This side view of Building 7 as it burns shows the extent of the fire in the building even though it is across the street from the main World Trade Center complex

Buckling: The windows in the upper right corner show how the building's exterior frame could no longer withstand the high temperatures

The video shows up-close shots of the lower floors of World Trade Center Building 7, located just across the street from the Twin Towers, and focuses in on the exterior metal beams of Building 7 as they begin to buckle as they are overheated. 

The buckling led to floors falling in on one another, causing the building to collapse.

Though the entirety of the collapse is not shown in the video, it does show how there is legitimacy to the explanation provided by the government's 9/11 Commission investigation.

The video was made by a local news reporter and was released through a Freedom of Information Act request.

Shot from the north side of the building on Barclay Street, and between the buildings in the background, the video shows the mass of raging fires taking place on the grounds of the World Trade Center.

The complex: Building 7, highlighted in blue, is shown burning in the video

Evacuated: There were no casualties in the building as everyone had left

THERE ARE STILL MORE OUT THERE... A HOST OF CONSPIRACY THEORIES STILL SURVIVE 

The main split in conspiracy theories comes from the divide over the role of the U.S. government in the attacks, with some feeling that authorities 'let it happen on purpose', while others think that they played a more diabolical role and 'made it happen on purpose'. 

Some of the theories argue:

-That no planes were used in the attacks, saying that the aluminium of the planes would not be able to penetrate the steel that made up the Twin Towers; instead, the New York buildings were subject of an internal, controlled demolition

-The Pentagon was shot with a missile by U.S. government officials

-That the U.S. purposefully avoided shooting down the planes and causing confusion to prevent military planes from scrambling in time

-.... while others are on the opposite end, some say that United flight 93, the one that crashed in a Pennsylvania field, was shot down by U.S. army jets

-That Israeli agents were involved, as FBI agents found five of them filming the New York attacks from the roof of an apartment building and celebrating afterwards

Though Building 7 was separate from the main World Trade Center complex, there were two pedestrian bridges connecting Building 7 to the main complex across the street, linking the buildings by the third floor.

In the video, viewers can see the glowing flames on what appears to be the sixth floor of the building, and as the camera zooms in, you can even see the metal bars of the exterior buckling. 

It is unclear when exactly during the day the video is shot, but considering the fact that the building is still standing it must be well before it's collapse which happened at 5.21pm. That said, the news reporter is the only person we see on the street, so the mass confusion and evacuation that took place earlier in the morning in the midst of the attacks had settled at that point.

At points, the news reporter seems clearly aghast, saying 'It's a surreal environment' and  'It's almost impossible to describe'. 

Official investigators say that after the South Tower fell at 9.59am and the North Tower at 10.28am, the pieces of the rubble did irreparable damage to Building 7, causing it to burn by floor by floor, getting progressively weaker along the way.

The investigation by the Federal Emergency Management Agency said that the collapse was caused by a combination of the damage from the debris - and not the impact of the debris itself- and lacking water in the fire sprinklers throughout the building.

The largest tenant of the 47-story building was the bank Salomon Smith Barney, but there were also offices of the CIA, the Department of Defence, utility company ConEd, and the Internal Revenue Service.

In the shadows: Building 7, the reddish building pictured to the left of the North Tower that is about half it's height, was considered part of the WTC site

Office space: Building 7 housed offices of the CIA, Department of Defence, utility company ConEd, and bank Salomon Smith Barney which was the largest tenant

Because of the time span of the events, everyone was able to evacuate the building and there were no casualties within Building 7.

Government analysts part of the 9/11 Commission said that all three of the buildings that fell in New York that day were due to 'total progressive collapse,' which means that when a building has extreme damage in one area, the entire structure of the building is weakened as a result.

Unless the damage is limited to one area, it will have a domino effect, moving on to lower floors in the building until it entirely collapses.

Conspiracy theorists take issue with that account, believing instead that the government was involved in the placement of explosive devices throughout the New York buildings, and even go so far to say that the incident at the Pentagon was caused by a missile rather than a plane.

Through the rubble: Looking around the buildings, viewers can see the blaze still alight where the Twin Towers had fallen

Destruction: All of lower Manhattan was caked in dust from the collapsed buildings