Maybe someone here will know, I think I once read in a magazine that a skyscraper in Toronto actually has a "glass floor", I know the picture in the magazine looked down on a baseball diamond, I thought it was right over it.
Also, a question of balance or not, it is nuts that that one acrobat does those long walks, no thanks. Why tempt fate? I guess he is well paid but it has a freak show quality on tv, you are just watching to see if he might fall. The wind too, is a danger for those people.
Nik Wallenda: he is attached in the last photo but on some walks, there is no attachment (looks like it in the first). Anyway, I stopped watching those shows. It's disturbing to me.