Perhaps the Windy City is tired of pesky tourists, because it scared the bejeezus out of a few last night: As NBC Chicago reports, Alejandro Garibay and three members of his family stepped out on "the Ledge" at the Willis Tower—four glass balconies on the 103rd floor Skydeck that jut out four feet, allowing visitors to look down 1,353 feet through a glass floor that can allegedly hold five tons—when they heard a cracking sound and saw the glass floor cracking beneath their feet. Garibay says they scooted off the balcony and called workers. "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," says Garibay. "When we pulled our phones to start recording and take pictures they asked us to leave right away."
Tower officials say it's no big deal and in fact the glass was doing what it was supposed to do: "Occasionally this happens, but that’s because we designed it this way," says a rep. "Whatever happened last night is a result of the protective coating doing what it’s designed to." He says that it was that top coating that cracked, and not anything structural; regardless, the Chicago Sun-Times notes that one of the ledges was indeed roped off this morning, its floor covered with carpet. Over at Gizmodo, Kelsey Campbell-Dollaghan runs down why it really wasn't a big deal, noting that the top layer of safety glass is called safety glass "because it stays intact, even when it shatters."