What is the simplest but most amazing and universally used invention of all time?

In my view all the inventions and discoveries that changed the living standard of humanity as a whole can be called the discoveries or invention of all the time. It depends on the time and age of the civilization. For ancient pre historic time discovery of fire was the greatest discovery. Then comes the discovery of wheel and so on. For the modern civilization invention of electricity can be considered as the discovery of all the time.

 

I gotta agree with the guys saying the wheel, is the most simple and important thing!

 

How about paper, or the wheel of course. When the wheel came around the world became better and faster a lot quicker then before. Without the wheel we would probably still be in the stoneage and maybe even then they had something similiar to it. It's got to be one of the biggest breakthroughs in human history inventing the wheel.

 

I'll go with compass. It's a very small device but has been very instrumental in the discovery of new lands. Imagine seafarers sailing on endless water and no idea what direction they are going. Early navigators used compass to discover new lands. While most of the lands they discovered became their colony, I think what's more important is that we discovered and shared our culture that brought the world closer.