What is the greatest invention in history?

Throughout life, humans realize that they lacked many necessary,  some of them essential and more important than others for everyday life, so, little by little, things of necessity were invented, such as, electricity, household appliances, phones...
But, what is the greatest invention in history? It is a difficult question but if we think a little, we will realize that almost everything we use in our homes works with electricity. As light or television, the light is essential for our lives and with television we entertain ourselves. Another invention is the telephone, since its creation it has been very important. It allows us to communicate remotely and today it is essencial for our day to day.
In conclusion, I consider that all invention are important, because they have been invented to make life easier, but among all of them, electricity is the most important because many inventions would not work without it.