For a brief moment, a few singularly unlucky tourists got to experience one of the most unique experiences the Windy City has to offer: Coming to know the sheer terror of fearing you're about to plunge more than 100 stories to your death.
According to CBS News Chicago, the protective layer of glass on the Willis Tower's Skydeck cracked into thousands of shards on Monday, terrifying a group of tourists - although nobody was ever really in danger. Something similar happened back in May 2014; again, nobody was hurt, or ever really in danger.
A spokesperson for the Willis Tower said the protective layer did what it was supposed to do, though he didn't explain exactly what they believe caused the glass to shatter. The spokesperson compared the glass to "a screen protector" on a smartphone and that it's intended to prevent scratches on the Willis Tower observation deck glass, and said it had been replaced late Monday.
But the brush with imminent death seemed real enough to terrify some small children, one witness said.
"There was a woman with two kids and they looked really pale and scared because the floor just cracked," witness Jesus Pintado said.
"I'm scared of heights in general so when I saw that happen, I was like nope, not going on," witness Karly Pintado said.
City officials contacted by CBS confirmed that the building's engineers are handling the problem (because let's be honest, there's no money in the city budget for that).
In 2014, officials closed all four observation boxes on the Skydeck after cracks appeared in the coating.
When the exhibit opened in 2009, engineers said the floor, which consists of three layers of half-inch thick glass, was designed to hold five tons.
Watch a video of the cracks below: