Willis Tower Skydeck crack shocked the family on tour, as the tourist attraction is closed down to visitors for an undetermined period while the 103^rd floor glass undergoes repair.

In a report by Chicago Tribune, Alejandro Garibay was posing for pictures at the clear box of the Willis Tower, along with his brother and two cousins, when he heard the snap.

"I had my palms on the floor and I could feel it cracking. Honestly, I was in shock, in disbelief. I was scared," he said.

"It was an awesome view. We were getting up and walking away and for some reason I thought it would be cool to get a picture of my cousins and brother," he said. "Then we started getting off and, as we push ourselves off, I could feel it cracking."

However, the CEO of MTH Industries, which installs the clear box that juts out of the building, said Garibay was never at risk because the only thing that cracked was the protective coating of the glass. That means the three-and-a-half-inch glass that is able to withstand five tons of pressure is undamaged.

The purpose of the protective coating "is to protect the structural glass from being scratched," Mike Swanberg told the publication. "It allows people to walk on the Ledge and get the full effect without putting booties on."

The Chicago Sun-Times talked to another spokesman for the building who confirmed that Garibay wasn't in danger of falling off, 103 storeys below.

"Occasionally this happens, but that's because we designed it this way. Whatever happened last night is a result of the protective coating doing what it's designed to," the spokesman said.

The Chicago attraction offers visitors a clear view of the Windy City as well as the Chicago River below. The four boxes were closed off to visitors on Thursday for routine inspection, said FOXNews.