Maybe you jumped on it. Maybe you played on it. Maybe you pretended to be free fallin' on it. But the glass "Ledge" at the Willis Tower in Chicago cracked yesterday. Talk about having nightmares for a while. Here's how it happened. 

NBC Chicago

According to NBC Chicago, a California family visiting got the big scare on Wednesday during a visit to Chicago's Willis Tower Skydeck, the 103rd floor tourist attraction atop the city’s tallest building.

"The bottom glass floor, one of the four glass enclosures jutting out from the side of the building, called The Ledge, cracked and shattered while Alejandro Garibay, his brother and two cousins were on it.

"Crazy feeling and experience," Garibay said to NBC Chicago.

Back in 2009 engineers said that boxes were composed of three layers of glass each about one half-inch thick. Officials told the press that "They were built to hold five tons."

But Garibay said before his group walked out into one of the boxes at about 9:50 p.m., they and other people were joking with staff about the strength of the boxes.

"They jokingly and confidently responded, 'It's unbreakable,' so we just went on," said Garibay.

While he and his family members were on the Ledge, Garibay said he heard cracking. They stepped off and alerted staffers.

Willis Tower staff members were totally shocked and asked everyone to leave right away. No word on when the attraction will be fixed."

To quote my dad, "They also said the Titanic was unsinkable." Seems appropriate now.