Skydeck at Chicago's Willis Tower Cracks Under Pressure

The translucent skydeck attached to the 103rd floor of Chicago's Willis Tower, the city's tallest building, showed major cracks after four men stepped on it Wednesday.

The California tourists, normal-sized adult men, stepped off the ledge when they heard cracking noises. They alerted staff, who appeared shocked and told them to leave after they snapped photos of the damaged ledge. Willis officials say the cracks are from a protective coating on the glass, not the glass itself. In fact, tourists are still allowed on the skydeck, except now there's a carpet obscuring the coating's cracks. The "unbreakable" skydeck is composed of three layers of half-inch glass built to hold five tons; it opened to the public five years ago.

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