Visitors to Chicago's Willis Tower SkyDeck got the fright of their life on Tuesday when the 103rd-floor glass ledge they were standing on appeared to shatter into thousands of pieces.
Thankfully for the people on the ledge, it was only the protective layer covering the glass that cracked - giving the impression the viewing platform was about to collapse.
The Willis Tower told local media that no one was in any danger and the protective layer did what was intended.
Jesus Pintado was there when the layer started to crack and managed to capture it on video.
"There was a woman with two kids and they looked really pale and scared because the floor just cracked," Mr Pintado told a local TV station.
The SkyDeck extends 1.3 metres from the 103rd floor of the Willis Tower. According to the company's website, the building is the tallest in the Western Hemisphere and the eighth tallest in the world at 110-storeys high.
The ledge attracts more than 1.7 million visitors annually.
Surprisingly, it's not the first time visitors have been left stunned with the protective layer cracking for the first time in 2014.
