Windows on the World was a complex of venues on the top floors (106th and 107th) of the North Tower (Building One) of the original World Trade Center complex in Lower Manhattan that included a restaurant called Windows on the World, it operated until 2001 when they were destroyed in 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 on which country?
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 on 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. 
9/11 conspiracy theories 9/11 conspiracy theories are conspiracy theories that attribute the planning and execution of the September 11 attacks against the United States to parties other than, or in addition to, al-Qaeda including that there was advance knowledge of the attacks among high-level government officials. Government investigations and independent reviews have found no evidence for the theories. Proponents of these theories claim there are inconsistencies in the official conclusions, or evidence that was either ignored or overlooked.