False-colour scanning tunnelling microscope image of atoms & electron bonds in a crystal of silicon. The black spots are the individual silicon atoms in a single unit cell". The bright regions between them show the position of electron bonds that hold the atomic crystal structure together. In this case, the image shows so-called "back bonds" that reach out sideways from the second layer of atoms in the surface of the silicon crystal. Scanning tunnelling microscopy is based on quantum mechanical effects, & records the surface structure of a substance at the level of the individual atoms. Magnification: x45 million at 35mm size. Blue tint. Ref: MICROCOSMOS, p. 204"