Officials at Chicago's Willis Tower say the popular tourist attraction is safe, even though a glass ledge jutting from the building's 103rd floor appeared to crack beneath the feet of a visiting family.
The see-through glass bays are known as The Ledge and extend about four feet (1.2 meters) from the building, which was once called the Sears Tower.
Officials say the family wasn't in danger when the cracks appeared Wednesday on a glass enclosure.
In a statement Thursday, Willis Tower says a protective coating covering the glass surface cracked, not the glass itself. They say the cracks don't affect the "structural integrity" of the ledge, which is designed to occasionally crack.
The ledges have proven to be a popular — if a frightening — experience since opening in 2009.