Running down the center of the space separating these two towers is the international boarder between the US and Canada. Or more specifically between North Dakota and Manatoba. Standing on that line I took the second picture looking up.
Note the symmetry with the boarder running through the center of the International Peace Garden in the three following pictures as I move further from the towers.
These are steel sections taken from the World Trade Center disaster site. They are to be used in a 9/11 memorial in the near future.