12. Slackline
The modern incarnation of tightrope walking is the slackline, a tightly strung strap over which the daring attempt to cross. It ain’t easy. Most slacklines, however, run horizontally between vertically positioned posts or trees. They don’t tend to run vertically between two windows, like in this piece. It asks us to stop and understand what we’re looking at, something most pedestrians won’t do, but should. No slacking allowed.