the national personnel records center fire of 1973.

several million military service records going back generations lost forever in mysterious fire that coincidentally destroyed the entire floor of the building in which these records were being stored.

strangely enough, fbi were unable to determine what caused the fire yet were somehow able to rule out one possible cause: arson. news narratives initially claimed without evidence that somebody's carelessly discarded cigarette was all to blame.

fire crews continued spraying the smouldering ruins of the 6th floor for a month for some reason, then demolition crews came in, and the rest of the building was at last brought up to meet basic standards of safety like having smoke detectors.

nasa even got involved with restoring many of the remaining records. though in the end only about 10% of the total records were ever recovered, with the most damage to army records from 1912-1960 and air force, 1947-1964.