Wind's interaction with the World Trade Center site is very unique. Check out the following video:
Every time the sound is heard it is different. Is this nature's way of manifesting a sound for the void that was created on 9/11 by the souls who left that day? Or is it the sound of the void created by humanity directing it's emotionally charged attention to this geographical location on this fateful day? Maybe both?
The sound is eerie, chilling and haunting. It's impact on human emotion is powerful.