A glass observation balcony on the 103rd floor of Chicago’s tallest building cracked and shattered while four tourists sat on it on Wednesday.
Willis Tower, the tallest building in the country, has glass boxes protruding from its SkyDeck, referred to as “The Ledge.”
Hovering 1,353 feet in the air, the glass is supposed to hold up to five tons.
Four tourists said employees bragged about the glass panels’ strength on Wednesday night.
“They jokingly and confidently responded, ‘It’s unbreakable,’ so we just went on,” Alejandro Garibay told NBC News Chicago.
He was on the glass with his brother and two cousins shortly before 10 p.m. when they heard the glass begin to crack. They alerted employees.
“I walked them over so they could see and they were totally shocked and asked us to step away and then proceeded to start calling staff and techs and I don’t know who else. When we pulled our phones to start recording and take pictures they asked us to leave right away,” Garibay said.
"Crazy feeling and experience," he wrote in an email to NBC Chicago.
A building official told NBC that the cracks were in the protective layer on the glass and that there was no danger to visitors.
Opened to tourists in 2009, the boxes consist of three layers of glass each one half-inch thick, NBC reported.
Sources: NBC News Chicago