There are actually TWO pieces. One was described earlier in the thread. It’s a dredging spoil that moved the edge of the river westward, whereas that state boundary is unusual in being defined as one shore of the river as of the date the border was agreed to. The other is within walking distance, and is a pier sticking out into the river toward Fort Delaware.
Yes, Baltimore is not in any county. There are two other such cities, though they are smaller (and I forget them).
There’s a spot near Santa Barbara, California, where you can watch the sun rise over the Pacific.
You can easily walk across Paris (either N-S or E-W) in about three hours. In how many other cities of that size can you do that?
Montreal is the world’s most populated island surrounded by fresh water. Ile Jesus (city of Laval) right next to it ranks number two. (and in the summer, the sun sets in the “north”).
The Eastern time zone is so wide that sunrise/sunset times at equal latitudes at the extremeties can be 90 minutes apart.