It is still amazing to me to see the breadth and depth of Google Maps applications. This one goes more to breadth.
A Google Map has been posted showing the boundaries of the Highland Park and New Brunswick Eruv. As I understand it, the boundary represents the walkable limits of the area for sabbaths and holidays - walking further would be work, not rest. There is also a very thin wire that is strung around town that shows this boundary to those are observant enough to see it.
Yet another very interesting mash-up.