And people say that they come from the monkeys.

The most unusual stone tool I ever saw was in the park museum of Rocky Mountain National Park. This was a stone twist drill, with right-hand flutes. It was only about 3" in length, and was probably used in drilling holes through seashell ornaments. I don't remember how old it was supposed to be; but human habitation in that region goes back 6,500 years. And pocket knives go back to ancient Rome. Few specimens survive, but at least a few can be seen in the National Knife Museum, in Chattanooga, TN.