What do you think are the historical events that most affected humanity?
The first answer is wars and war making tools such as gun powder. The gun made it where one man could fight off many men if he is a good shot.
The thing that had the largest impact on the most people first was the printing press.
After the printing press the telegraph and Telephone. Then Electricity and transportation.
Today it is the WWW the ability to communicate with others in a split second world wide.
I will predict the next thing that will impact us all is the RFID Microchip.
War definitely. It affected so many lives and it was unnecessary.