When did the wtc collapse?

September 11th 2001:

The South Tower collapsed at 9:59 after burning for 56 minutes

The North Tower collapsed at 10:27 after burning for 102 minutes

The WTC 7 Collapsed 30 minutes after the WTC 1 North. WTC burned for more than 6 hours with out a plane hitting WTC 7
The South Tower collapsed at 9:59 after burning for 56 minutes

The North Tower collapsed at 10:27 after burning for 102 minutes

Another tower, WTC 7 that collapsed at 17:20 after considerable Controlled Demolition by the Owners.
The terrorist attack on the World Trade Center twin towers was on September 11, 2001. On that day both towers collapsed after each had an aircraft flown into them. This day will never be forgotten.
The Twin Towers of the New York World Trade Center collapsed at 9:59 AM and 10:28 AM EDT on September 11, 2001.

The buildings were targeted as part of a terrorist campaign against the United States by Islamic fundamentalists opposed to the US actions in the Middle East. The attack was funded in part by the Al Qaeda movement led by Osama bin Laden (also Usama), a Saudi expatriate who became active in guerrilla and terrorist movements.

The attacks on the Pentagon, in NYC, and in Pennsylvania took place on September 11, 2001. At 8:46 AM EDT, American Airlines Flight 11 was crashed into the World Trade Center's North Tower, followed by United Airlines Flight 175, which hit the South Tower at 9:03 AM. The South Tower collapsed less than an hour later at 9:59 AM, followed by the North Tower at 10:28 AM. As many as 2750 people, including the hijackers and passengers of the two planes, were killed.
September Eleventh, 2001. Known as 9-11 because September is the ninth month and it happened on the eleventh day.
September 11, 2001
they did fall down due to the explosive forces of the 747 planes.

they fell at September 11 2001 or 9/11