A trip to the top of the tallest building in Chicago turned into an even more harrowing experience in the sky for some visitors Monday when a protective coating on the glass-floored balcony began to crack beneath their feet.
The incident happened on the Willis Tower's 103rd floor, the location of the tourist attraction Skydeck Chicago where visitors can get a panoramic view of the city, Lake Michigan, and even parts of neighboring Indiana.
The attraction also features four glass enclosures collectively called The Ledge, which opened in 2009 and give tourists the feeling of standing suspended in midair 1,353 feet above the ground and 4 feet away from the building.
Visitors at the Ledge are treated to unobstructed views of Chicago from the building's west side and a heart-stopping vista of the street and Chicago River below — for those brave enough to look straight down.
But Jesus Pintado told CBS Chicago the experience went to a new level of fear after there was a noise and the floor appeared to crack.
“There was a woman with two kids and they looked really pale and scared because the floor just cracked,” he told the television station.
Each Ledge box is comprised of three layers of half-inch thick glass, laminated into one seamless piece.
Pintado's wife, who already is nervous about heights, said witnessing the moment was enough for her.
“I’m scared of heights in general so when I saw that happen, I was like nope, not going on,” Karly Pintado told CBS Chicago.
While scary, the protective layer is what covers the actual glass bottom, according to FOX32.
A building spokesperson told WTHR that no one was ever in danger on Monday, and The Ledge was immediately closed after the incident.
"The protective coating which acts like a screen protector for the Ledge experienced some minor cracking," a spokesperson told WTHR. "We replaced the coating last night and the Ledge is open for business as usual."
The Associated Press contributed to this report.