Negotiated Border by Yadiel J Rivera-Diaz highlights 3 border walls of Berlin, Israeli-Palestinian and Mexico-USA. Rivera-Diaz claims that border lines establishe "a distinction between two groups" which can be "political difference, unequal capital distribution, and ideology" and "regardless of their intention for separation, these borders have become places of interaction between the two sides".
Rivera-Diaz, Y.J.  Negotiated Border. [online] http://www.topophilia.org/blog/negotiated-border