What is one of the most important inventions of all time and why?

Today for our thinking question we had to answer this question: What is one of the most important inventions of all time and why? It was a pretty tricky question. Some of our ideas were: the internet, robotics, the TV, cars, electricity, the incubator, computers and laptops, bags, the seat belt, the traquilizer dart, the flushable toilet and even war. The most popular suggestion was the phone. We had to think about why our choice was the MOST imporant- that was harder still. 

Here are two people's thinking about this question:

"One of the most important inventions of all time is the airplane. Airplanes can take you where you want to go in the world like Korea, Australia, China and NewZealand. The reason why it was so important is because it made the journey much faster. You can now travel to Korea in a few hours, instead of it taking days by ship. 
An airplane can also be used for sky diving and also the airplane can go up into the air and you can open the door and jump!
Airplanes also can be used for delivering products from one country to another."
By Daniel Kim


"In my opinion I think numbers are the most important invention of all time, because if there was no numbers there would be nothing at all!
Some poeple might think that medicine is better because it saves lives, but think about it...when people make medicine how do they know how much stuff to put in it without numbers? 
Also, telling the time would be hard. For example,
"See you later!" said Bob
"Later when?" asked John
"I don't know!" replied Bob
See? If there was no numbering system we would have nothing.
In conclusion, I think numbers are the greatest invention of all time!
By Eliot H

So what do you think? Make sure you justify your answer!