A staggering piece of engineering: 1,700 feet of curving steel arch standing 876 feet above the New River. From 1977 until 2003 it was the longest single-span steel arch bridge in the world; it's still the third longest. From the Canyon Rim Visitor Center on the north side there are two observation decks and a long boardwalk-and-staircase trail down to a lower platform that offers the best photo.
For a more visceral encounter, the privately run Bridge Walk takes small groups (in harnesses, on a permanent catwalk underneath the highway deck) the full length of the bridge — a serious bucket-list experience for anyone comfortable with heights.