It doesn't officially open till the 28th of March, but a few lucky visitors got an early glimpse of the Grand Canyon's Glass Skywalk. The see-through sidewalk juts out 70 feet over the cliff's edge, and the only things standing between you and the 4,000-foot chasm below are a lot of steel and 4-inch thick tempered glass. The glass plank can hold up to 800 people (each weighing 175 lbs). I'm pretty chicken when it comes to heights, but this is something I'd totally do, especially after seeing the video (post-jump). Only $25 for admission.