Glass floor is transparent section of a floor used for observation decks in order to facilitate viewing directly beneath where one is standing. Usually glass floor made of a reinforced glass, the most common use is as a tourist attraction. Glass-bottom boats are popular for allowing a better view into the water. Glass as a flooring material is used in both residential and commercial structures. Special hollow glass blocks known as glass pavers are often used in combination with a metal frame.
The highest glass floor above ground is the novel outdoor application of the Grand Canyon Skywalk at 4000 feet (1219 m), operated by the Hualapai Indian tribe. Some people have made a mistake about the highest glass floor with the building in Chicago. You can see the comparison of the height here:
And here’s the pictures of the Grand Canyon Skywalk, See how incredible this structure is: