Very fast moving flying objects you can see, they are not birds, they
cast large shadows on the towers.
http://youtube.com/watch?v=JYqEMBXC7mE
http://youtube.com/watch?v=kHI1etfHuqA
http://youtube.com/watch?v=4fMn159Onq0
http://www.youtube.com/watch?v=AU9607IVOiY&mode=related&search=
Alfons v911t