The NIST determined the fires to be the main cause of the collapses; the plane crashes and explosions damaged much of the fire insulation in the point of impact, causing temperatures to surge to the point the towers' steel structures were severely weakened.
As the heat of the fire intensified, the joints on the most severely burned floors gave way, causing the perimeter wall columns to bow outward and the floors above them to fall. The buildings collapsed within ten seconds, hitting bottom with an estimated speed of 200 km/h (Getty Images).
The question refers to the twin towers on 9/11. The first tower was hit about 12 floors from the top. The second was hit 17 minutes later about 28 floors from the top. That means the second tower was supporting over twice the weight by a damaged section of the building on fire and that tower collapsed first.
In total, twenty survivors were pulled out of the rubble. The final survivor, Port Authority secretary Genelle Guzman-McMillan, was rescued 27 hours after the collapse of the North Tower.
Archaeologists at the New York State Museum are piecing together a boat found deep in the muck at the site of the former World Trade Center. The boat dates back to the Revolutionary War. It was found 15 years ago and is now getting a permanent home, even though part of its journey to New York remains a mystery.
This Computer Simulation Explains How the Twin Towers Fell
What was the twin towers' original purpose?
In 1939, when Europe was on the brink of another world war, a group of business and trade associations created the first World Trade Center dedicated to promoting world peace through world trade.
The North Tower (WTC 1) was the first building to be hit when American Airlines Flight 11 crashed into it at 8:46 a.m., causing it to collapse at 10:28 a.m. after burning for one hour and 42 minutes.
Tully crews worked 24-hours a day, seven days a week, moving tremendous quantities of debris, transporting the debris to the Fresh Kills Landfill in Staten Island which was re-opened for the recovery operation. Tully trucked some 500 loads of debris per day.
Did people leave the second tower before it was hit?
Of the 183 subjects from WTC2 for whom exit time was reported, 20% were out of the building before WTC2 was struck, 57% escaped before 9:30 a.m. (See Table 6).
The terrorists did not have the capacity to destroy the United States militarily, so they set their sights on symbolic targets instead. The Twin Towers, as the centerpieces of the World Trade Center, symbolized globalization and America's economic power and prosperity.
How fast was the plane going when it hit the South Tower?
The airplane crashed nose-first into the South Tower's southern façade at a speed of around 587 miles per hour (945 km/h; 262 m/s; 510 kn), striking floors 77 through 85 with approximately 9,100 U.S. gallons (34,000 L; 7,600 imp gal) of jet fuel on board. All passengers on board were killed instantly.
How long after the first tower fell did the second fall?
What came next shocked ordinary people and experts alike; 47 minutes (9:59 am) after the 2nd plane hit the South Tower it suddenly collapsed. The North Tower, which had been hit first withstood the impact intil 10:28 am, but it too fell.
The September 11 attacks were the deadliest terrorist attacks in human history, causing the deaths of 2,996 people, including 19 hijackers who committed murder–suicide and 2,977 victims. Thousands more were injured, and long-term health effects have arisen as a consequence of the attacks.
On September 11th, 2001, the Twin Towers swayed more than they were designed to due to the impacts of the planes. While the towers were built to sway up to about a foot in high winds, the impacts caused them to sway significantly more, with some estimates suggesting several feet, possibly up to TEN feet.
How long did it take to clean up the twin towers after they fell?
The work took ten months and involved employees from dozens of City, State and federal agencies and the tireless efforts of responders, laborers, contractors, volunteers, and community organizations.
Only twenty people were found alive and rescued from the rubble and remains of the collapsed World Trade Centre Twin Towers on September 11th and 12th, 2001. This includes a man who dug himself out, and a firefighter group who were in a stairwell.
Were people still alive in the North Tower when it collapsed?
Because of the angle at which Flight 11 impacted, nobody above the 91st floor of the North Tower was able to escape the building, trapping 1,344 people. All of them died due to smoke inhalation, burns/incineration, jumping/falling from the building, or the eventual collapse of the tower.
Did anybody who jumped from above the impact zone of the World Trade Center survive the fall? Not really. There is the “Black Tag Lady” story. Apparently a woman (most likely from the tower, not the plane) had momentarily survived the fall from the impact of the plane.
The World Trade Center contained almost 10 million square feet of rentable office space. This size equaled nearly three Disneyland Parks. In 2001, the World Trade Center housed more than 430 businesses from 28 different countries. The World Trade Center had its own zip code: 10048.
Did you know? Fires continued to burn in lower Manhattan for 99 days after the attack. Eventually, the pile stabilized enough that construction crews could start using excavators and other heavy equipment.
