September 11 attacks
The September 11 attacks (also referred to as 9/11) were a series of four coordinated terrorist attacks by the Islamic terrorist group al-Qaeda against the United States on the morning of Tuesday, September 11, 2001. The attacks killed 2,996 people, injured over 6,000 others, and caused at least $10 billion in infrastructure and property damage. Additional people died of 9/11-related cancer and respiratory diseases in the months and years following the attacks.
The NIST World Trade Center Disaster Investigation
During the September 11th terrorist attacks, two jet airliners struck the Twin Towers of the World Trade Center (WTC), one to each tower. As a result, the two 110 stories-tall skyscrapers collapsed, causing complete destruction to the entire WTC complex and killing 2,997 people. The South Tower collapsed at 9:59 a.m. (EDT) after burning for approximately 56 minutes. 29 minutes later, the North Tower collapsed having burned for 102 minutes. When the North Tower collapsed, debris fell on the nearby 7 World Trade Center, damaging it and starting fires that burned for almost seven hours, compromising the building's structural integrity. Seven World Trade Center collapsed at 5:21 p.m. (EDT).