In line with the greatest invention thread the opposite occurred to me.
There have been some mind-blowing inventions, but being human we've also come up with some real terrible ones.
So if you had the chance to uninvent one of them, which would it be?
My two biggies would be religion and the atomic bomb. Between them they've killed so many people it's untrue.
Trivia: Did you know that there are more people alive today than have ever died in the past?