Photo of the terrorist attacks of September 11, 2001

Flight 175 of United Airlines a second before the collision with the southern tower of the World Trade Center. The North Tower is already on fire. (Reuters / Sean Adair)

Smoke is pouring from a hole in the wall and from the upper floors of the northern tower of the WTC in New York, after a collision with her American Airlines flight 11. (AP Photo / Richard Drew)

Flight 175 of United Airlines a second before the collision with the southern tower of the World Trade Center. The North Tower is already on fire. (Reuters / Sean Adair)

An explosion in the southern tower during a collision with her plane flight 175 United Airlines in New York, September 11, 2001. The plane crashed into the building at a speed of 945 km / h. (Reuters / Sean Adair)

Collision of the aircraft with the southern tower of the World Trade Center. On board there were 56 passengers (including 5 hijackers). (Spencer Platt / Getty Images)

Explosion of 3,800 liters of fuel remaining on board the aircraft during a collision with the southern tower of the WTC in New York. (AP Photo / Ernesto Mora)

Two women, deceiving each other, look at the burning WTC buildings after the terrorist attack. (AP Photo / Ernesto Mora)

For the Empire State Building are visible burning twin towers. (AP Photo / Marty Lederhandler)

A cloud of smoke from the WTC buildings in lower Manhattan. A snapshot from a satellite of the US Geological Survey that flew over the area around 9:30 on Tuesday, September 11, 2001. (AP Photo / USGS)

People hanging from the windows of the northern tower of the WTC after the attack. (Jose Jimenez / Primera Hora / Getty Images)

A man jumps from the upper floors of the burning northern tower of the WTC. (AP Photo / Richard Drew)