What invention had the greatest impact on humanity and why? [View all]

I'm sure there are a lot of answers but IMO, the plow is the answer.

Early human agriculture was labor intensive where people would use their hands and fingers to plant seeds. When someone began dragging a stick creating a furrow planting required less people. The stick was replace but a bigger stick free more people from farming. Eventually, the design of the plow was discovered and when people used animals to pull the plow it allowed one or two people to do the work of many.

The plow gave people more time to do things like weaving, pottery, baking, etc.. With more free time, people began studying the stars, developing math not only to determine how much they had but how it could be used for building. In short, the plow allowed the beginnings of astronomy, math, science, building, etc., which furthered the growth of human society. It is from the humble beginnings of the plow we owe to everything we use today.