Cira Green is a newer location for downtown since its only a few years old. Located on the roof of a parking structure along the Schuylkill, surrounded by the Cira Center buildings, its one of my personal favorites just for relaxing on a nice day. But for photos it works nicely as well. The grounds are simple with a few areas to get cozy in the grass lawns that it has. It has a couple spaces that work well to get the skyline involved and like I mentioned, you are in a valley between two skyscrapers so its always nice to work them into some shots as well.
*As of now, there are no formal permits needed but this is subject to change.