The Skydeck at Willis Tower is open today after repairs to its glass boxes.
The fourth of three glass boxes that look down from 1300 feet was opened this morning after the glass cracked.
A family from California visited Wednesday night and decided to take some pictures.
But, when they stepped out they say they felt the glass crack under their feet.
Officials at Willis Tower say it was the protective coating on the glass surface that cracked.
They say the public was never in any danger.