Grand Canyon Skywalk – Simply Amazing!
If you happen to walk on Grand Canyon Skywalk, you are walking on the highest possible platform in the world! Just see the comparison height below, it’s amazing!
The Grand Canyon Skywalk, a horseshoe-shaped glass walkway, at a 1,200 meter (4,000 ft) height above the floor of the canyon exceeds those of the world’s largest skyscrapers.

Skywalk protrudes 20 meters (65 ft) beyond the edge of the canyon. The walls and floor are built from glass 10.2 cm (4 inches) thick. The glass on both edges of the floor is tinted and can be used as a “safe zone” by scared visitors. The Skywalk is capable of holding 70 tons of weight, the equivalent of 800 people weighing 80 kg (175 lb.) each, however the permitted capacity is limited to 120 persons.



Info via Wikipedia.
By the way, here is a related video from Youtube:
