Mostly Old Man’s Beard, also known as Wild Clematis.
Amgen, a big biotech company, is on the Seattle waterfront, across many railroad tracks from a main road. They had a pedestrian bridge built over the tracks, and in reference to their line of work, they made it look a bit like a big strand of DNA on its side. The “Helical Bridge” isn’t really a helix. It’s actually three leaning, overlapping tubular arches that support the walkway, but the rhythm of the structures does have a helical vibe. Here, of course, I don’t show much of the bridge itself, so you’ll just have to imagine (or google) it.