What is the sharpest thing in the world?

The sharpest thing in the world is considered to be a tungsten needle used in electron microscopes, which has a pointed tip that tapers down to a single atom. This needle can be as thin as one atom wide and can cut through practically anything on a molecular level. It has been used to create extremely precise images and measurements in various scientific fields, including materials science, biology, and nanotechnology. However, due to its delicate nature and cost, it is not commonly used outside of specialized laboratory settings.