In your opinion, what is the greatest invention ever?

Hi, folks!
In my opinion, the greatest invention was the electricity, one of the most important forms of energy which also includes natural gas, oil, nuclear powder and so on. In this case, I will focus on electrical energy and one of its purposes of providing us a comfortable living. Due to the energy, we are able to watch tv, have a warm shower, use the computer and moreover the internet, listen to radio or cd, recharge our mobile phone, digital camera and other devices or even cook a delicious dinner in the end of a hard working-day. So, for me it was a great invention.
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in my opinion is the phone,never a man did other invention as good as this!!!some inventions are very good,but not outweigh!!!
Hmmm, I think so is how the humanity learned to use the electricity. Because a lot inventions today need it. But, I could talk about the internet, wheel and others.
Sypher 1 1 24
I wouldn't say that is the book the most important invention ever just because I think the the ability (or the idea) to write comes before the idea to put written things in a piece of paper (or in rock or in a piece of animal skin).

Through writing we started to share knowledge to people far away from us both in distance and time. The knowledge could be stored and accumulated, and based on this accumulation we could reach to new knowledges and inventions, whose ones improved our lifes and our ability to see and understand the universe in which we live.

All that is possible because things were written and then read and then written and read again. The evolution of our knowledge comes in written forms accumulated through the endeavor of many generations, and so it will continue while life forms exists in the universe.
The computer, without a shadow of a doubt.
without it the world would not be the same! :)
Hello Everyone!
In my opinion i think the biggest invention that the world ever had was the "Wheel", because imagine the things that are too much heavy being taken from a place to another without wheels, by the way we couldn't drive a car, we couldn't fly in a airplane, because how the airplane could stop in the ground?, anyway, we couldn't do a lot of things if we haven't "Wheel" like our assistence.
Therefore i'm sure that "Wheels" came to help us very very much.