borders: multifeatured lines

Tijuana-San Diego border  (source:Wikipedia)

There are many boundaries in the world, one of the most official ones in big scale are borders, in other words, political boundaries. How often do we confront with boarders personally? How do we understand them socially?

It is very hard to generalize the notion of border as it depends on us and on the boarder we confront with, but there is a common, social agreement on boarders, their visualization - political map, their definition - laws, their realization - boarder surveillance constructions. There are so many different understandings about the border that it makes boarder variable!