CHICAGO, Illinois -- Video posted to social media shows cracks on the glass floor of The Ledge attraction at Willis Tower on Monday.
The video was posted by a Skydeck visitor on Facebook.
A spokesperson for Willis Tower issued a statement saying, "The protective coating, which acts like a screen protector for the Ledge experienced some minor cracking. No one was ever in danger and the Ledge was immediately closed. We replaced the coating Monday night and the Ledge was open for business as usual yesterday."
The protective coating has cracked before. In May of 2014, tourists were taking photos on The Ledge when the floor beneath them seemed to shatter.
"All we see is the glass shattering," said Tony Saldana, of Crest Hill, in 2014. "We're thinking the whole thing's coming down. We're thinking we're about to fall 103 stories."
At that time, Willis Tower spokespeople explained the protective coating is designed to keep The Ledge from getting scratched up by visitors.
"It did what it's supposed to do. It's designed to crack on those rare situations where there's some kind of impact to protect the structural piece below," Randy Stancik, Skydeck Chicago general manager, said in 2014. "Never at any time was anybody in any jeopardy here."
The Ledge is comprised of four glass enclosures which extend 4.3 feet beyond the building, giving visitors a 360-degree view.
Willis Tower Skydeck ledge cracks: Video