The atomic bomb and the hydrogen bomb.
Cheap food additives and sugar substitutes
cigarettes First it gives relief then it gives Cancer
cellphones or biological weaponary ... both are hazordous to innocent people when misused
Robots with the potential to become more intelligent than we are. And, I think it's really stupid that people are trying to create a black hole. They want to consume the earth and kill everyone? Great idea.
all the new illnesses the drug companies pretend to exist every time they make a new pill.