I also want to point out that the tower was stated to be 53-stories before and during the construction process. Overlooking the rendering and an elevation, it looks as if where Pyramid Club is now was supposed to be open air, including seemingly no large floor to floor glass panels and definitely an open air roof with the columns supporting the "roof" and crown
Mellon Bank Center rendering--Image by KPF by
Philly SkyGuy, on Flickr
Mellon Bank Center rendering close up--Image by KPF by
Philly SkyGuy, on Flickr
Mellon Bank Center crown elevation--Image by KPF by
Philly SkyGuy, on Flickr