>> the quarter inch top pete of glass is designed to protect the 1 1/2 inch thick structural glass. the sole purpose is to keep the structural glass free of scratches. >> oh, my god. take the picture! >> reporter: the ledge on the sky dack now back in business, and even these guys admit after the scare of their lives. >> for the record, an awesome view. awesome building. >> reporter: the view from up top made such an impression on them they may just come back for more. george howell, cnn, chicago. >> boys, just don't step out there together. >> yeah. i'm a man of girth. it's okay. but there's no way i'm going out there with three other hefties to stand on some glass sheet. >> i wouldn't even go out there. i stood at the delineation line between the floor and the glass and i did this -- >> looked over. >> okay. that's was far as i got. >> i know they say it's not supposed to happen. not supposed to shatter. >> not buying it, people.