September 11th attack - United Airlines Flight 175 crash into the South tower

What happens in this video ?

September 11th attacks in 2001 – Videos of the Boeing 767 from United airlines that hit the second tower of the World Trade Center (WTC) in New York. The Boeing 767-222 took off from Boston, Massachusetts to Los Angeles, California. It crashed into the South Tower at 9:02:59 a.m. local time. All the 65 people onboard were killed instantly. The crashed caused the collapse of the South tower at 9:59 a.m. (having burned for 56 minutes in a fire caused by the impact and the aircraft fuel) while many people were still inside. In total 630 people died in that tower, fewer than half the number killed in the North Tower. There are less casualties than in the North tower as some occupants start evacuating as soon as the North Tower was hit a few minutes before.
The event was covered live by television broadcasters from around the world who had their cameras trained on the buildings after the first crash in the North tower.
Click hereafter for details about the 4 hijacked aircraft during September 11th attacks.