On Nov. 9, 25 years ago, the 155km-long Berlin Wall fell. Not long after, large groups of people charged into the intimidating Ministry for State Security (Stasi) headquarters where they saved files from destruction by ministry staff. It was later discovered that the 158km of files and films found were the results of information gathered by 90,000 Stasi staff and 150,000 informers to keep strict control over East German society.