The glass at McCormick Place in Chicago is a lethal obstacle for birds
I highly encourage anyone who had birds crash on their windows to install white dot stickers. I installed some last spring on my windows and not a single bird crashed on them since.At first they look a bit odd, but after a week they were almost invisible, turns out the brain is really good at hiding things we don't care to see. They are a bit of a pain to install but it is well worth the effort.