911 Attack: Where do the people had fallen after jumping from the WTC bldg?

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I was watching the videos from youtube about the people who are jumping from the Twin Towers then falling to the ground. Now I wonder where did they fall? Is that the ground part already of the street? Or the they have fallen on to the top of another building? Because I remember before that there was discussion here in our house then someone even stated that there was a news that people were able to hear that there is somebody falling to the ground because of the sound. I am wondering as well if there is really an inside job when the 911 Attack happened because I also saw it on video that there is even a protest indicating that it was inside job.