What is the oldest human-created artifact that has mattered to you? Why/how does it matter?

The oldest human creation that has mattered to me is the Wheel. The wheel is important today because it helps us get to place to place, get us to school, or just go for a nice ride in the park. The wheel is one of the oldest inventions, and when you think of the first wheel, you think of a stone circular object that rolled when the cavemen pushed it. Also with out the wheel we would have to stay close together, and if we had family in other states, it would take forever to get there, and may not make it if there is a bad storm or anything. Also without the wheel we would not have cars. I think that the wheel was the most important invention that is still used today.

http://upload.wikimedia.org/wikipedia/commons/2/24/Wheel_0062.jpg