Mr. Bobby Healy:

I will give the examples of cranes. We scour the area every day looking for new cranes being erected because they are not notified quite often. Cranes would be a good example of a hazard. We would be aware of that and block it in our airspace. Similarly, if there is a concert going on in Millennium Park, which frequently happens, ice skating and things like that, we block that area in our air space and we do not fly over it.