Visitors at Chicago's Willis Tower Skydeck got a scare Monday evening after the attraction's protective layer cracked under their feet.

A spokesperson for the tower said no one was in danger because the protective layer acted as it was supposed to, according to CBS Chicago.

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The shattered layer was replaced Monday, and the Skydeck reopened Tuesday, USA Today reported.

Jesus Pintado, who was visiting with his family, captured the glass breaking in a video posted to Facebook. The video, which depicts the ledge’s protective top layer splintering into thousands of pieces on the 103rd floor, has gone viral in the days since it was posted.

The Skydeck gives tourists a view of the city and nearby Lake Michigan. The 1.5 million people who visit the iconic attraction each year are encouraged to stand on the deck’s ledge and see the city below them.

The protective layer also broke in May 2014. No one was injured in the incident.