It is estimated that up to one million people were killed during communism in Eastern Europe - but there is no clear figure for those imprisoned, persecuted or spied on.
The whole issue of what to do about the past - forget, forgive, confront - is a live and contentious one in countries like Poland, Romania and the former Czechoslovakia.
And as most formerly communist countries have started to open their secret police archives, ordinary people are beginning to get a sense of how far the state intruded into their private lives.
European affairs correspondent Oana Lungescu - one of many Romanians who was watched - investigates.
People like Ioana Voicu Arnautoiu - who was adopted when she was two - grew up without knowing who she was. Her parents were partisans and were in hiding, resisting the regime for nine years. She was born in a cave.
Finding the secret service files on her family - 85 volumes - was "a great experience" for Ioana because it provided a tangible, detailed family history.
For others it is a violation and a reminder of the permanent fear of being informed on. The regime kept tabs on almost everyone, people who told jokes, those who had relatives abroad and others who were interested in learning foreign languages.
Oana describes her own file as "a perverse time machine" that reveals a truth, but not her personal truth.
How are people dealing with such a large-scale revelation?
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