A sidewalk is normally situated next to something else, namely a street or road. The “side” in sidewalk implies that it’s not the main event; it’s a sideshow. A more accomodating, if looser, definition for a sidewalk is a path through which (mostly) pedestrians go through.
High Line Park in Manhattan fits under the latter definition. Inaugurated in 2010, High Line is a unique concept that I hope gets replicated in other cities. The park is located on the former site of an elevated freight rail line. The rail line sat unused for two decades, and there was talk of tearing the whole thing down, when a brilliant community member had the idea to turn the rail line into a park.
The well-manicured park is largely landscaped with native vegetation that was growing on the tracks after the rail line shut down. The views from High Line are spectacular. The park is the equivalent of 3 or 4 stories off the ground, so you’re close enough to the street level to observe pedestrians, while being high enough off the ground to be able to take in sweeping vistas of the New York City skyline. High Line currently stretches about ten city blocks. The second phase of the park, currently under construction, will extend the length of the park by at least another ten blocks.