One (above) is a round bridge sprouting out from the Grand Canyon rim, suspended 1219 meters above the canyon's floor; the other (below) is a wooden platform that extends into the void, then twists back and puts its "feet" into the mountainside, located about 600 meters above the Aurland Fjord in Norway.
They are both planned to open soon. The Grand Canyon Skywalk has been designed by MRJ architects; the Aurland Lookout by Saunders & Wilhelmsen . Both promise mind-numbing views - indeed, this is not stuff for those who know vertigo. The Skywalk will be made mainly of glass (so there will be, like, nothing under your feet). The Aurland Lookout looks sturdier and safer but may feel the opposite to those who will walk on it, mainly because there is only a clear glass barrier "closing" the platform at the end. According to Wallpaper, "the whole structure has the feel of a giant diving board, ready to pitch you into the void". Here is the same sentence, just without the words: