Invisible buildings

Inspired by Dr Joolz' post on East Berlin, I have begun to muse on invisible buildings.
That is, huge buildings which nevertheless, the local inhabitants simply do not see.

They are unmarked on maps, have no signs attached and remain invisible to those who live amongst them.
The collective farms in Estonia were invisible yet every five miles or so we would spot one and the cry would go up 'Collective farm' and we would photograph it.
When we asked our Estonian friends about them, they said they were invisible because they were not part of Estonian History and therefore meant nothing.
But they then revealed they had spent time working on them as students, under Soviet occupation (illegal).
Now they littered the landscape, rusting and broken.

Ofcourse, I wanted to immediately apply for a European grant and get massive funding to do a cultural geography of collective farms, with narratives of identity, and make a cutting edge new museumology exhibition of narratives of identity, or resistence (in Estonian terms) and the buildings of the collective farms.
Now I just need to find a partner.