A California family had quite the scare while visiting Chicago’s Willis Tower.
They went out on The Ledge—a glass enclosure that lets you look 1,353 feet below—only to find it was cracking beneath them.
Alejandro Garibay said he and his family were terrified that the glass had shattered.
Turns out, it wasn’t the glass. A spokesman for Willis Tower told WGN TV that a protective coating on the glass cracked.
“This coating does not affect the structural integrity of The Ledge in any way,” Brian Rehme said in a statement. “Occasionally, the coating will crack, as it is designed to in order to protect the surface of the glass.”
The Ledge opened in 2009, giving tourists a view from 103 stories above the city. The four glass enclosures extend more than four feet beyond the building. The glass is 1 1/2 inches thick.