Surveillance is about seeing things and, more particularly, about seeing people. (Lyon 2007: 1)

For simplicity I have arranged this [classification of surveillance] largely in a series of discrete either/or possibilities (e.g. visible or invisible, gathered by a human or a machine). But there may be continuous gradations between the extreme values (e.g. between the visible and invisible). (Marx 2002: 14)

If someone needed to go to a house physically next door to their own but in the neighbouring city, it was a different road in an unfriendly power. That is what foreigners rarely understand. A Besź dweller cannot walk a few paces next door to an alter house without breach.

But pass through Copula Hall and she or he might leave Besź, and at the end of the hall come back exactly (corporally) to where they had just been, but in another country, a tourist, a marvelling visitor, to a street that shared the latitude-longitude of their own address, a street they had never visited before, whose architecture they had always unseen, to the Ul Qoman house sitting next to and a whole city away from their own building, unvisible there now they had come through, all the way across the Breach, back home. (Miéville 2009: 86)