Corrections to the copy of the appropriate documents were made and reprinted and then the original copy was destroyed as well. This continued alteration applied to every kind of literature or documentation. No evidence of previous documents were left, they were incinerated. The past was always being brought up to date. This way, every prediction made by the Party could be shown by documentary evidence to have been correct. Winston puts all related documentation into a memory hole, thus sending any evidence of altered data to a large furnace in the center of the building.