A chilling but illuminating legacy of the former East German state is the archives of its Ministry for State Security, the dreaded Stasi.
The files compiled by 91,000 professional secret policemen, with the assistance of about 180,000 "unofficial collaborators" or informers require 111km of shelf space.
The card index system required to navigate that much information runs to 39 million cards.
Since 1991, nearly three million people have asked to see their files. The files have also been used to vet 1.7 million civil servants.
The Stasi made a science of recruiting collaborators, says Dagmar Hovestadt, spokeswoman for the Federal Commissioner for Stasi Records.