Willis Tower officials said the protective coating cracked, but the glass underneat was structurally sound. (Alejandro Garibay)
Alejandro Garibay took this photo of The Ledge at the Willis Tower Skydeck after the protective coating shattered. Officials say the glass enclosure is still sound. (Alejandro Garibay )
Three of four glass enclosures that make up The Ledge at the Willis Tower Skydeck are open after the protective coating of one cracked. (WLS)
CHICAGO (WPVI) -- The Willis Tower Skydeck's The Ledge cracked - but it's supposed to, according to a spokesperson, who said only the protective coating of the glass box that protrudes from the 103rd floor of Chicago's tallest building cracked.