At 1,353 feet above the ground, a family from California was inside one of the glass viewing boxes at Chicago's Willis Tower when the floor panel shattered. Just before stepping into the box, the family was told by a tour guide that the glass was unbreakable
Willis Tower Glass Viewing Box Shatters Under Tourists' Feet (29 May 2014)
milwhcky
@ 2014-05-29 12:53:08
The glass that shattered was an 1/8 inch thick coating that keeps the 3.5 inch thick glass floor from getting scuffed. No one was in danger of falling when it shattered, but I'm sure it was frightening!