The detection of atomic-size defects by atomic force microscopy (AFM) is demonstrated. For example, the dark grooves in the image of the surface of the incommensurate layered telluride phase TaGe0.355Te2 (see Figure) indicate a defect. The origin of this incommensurate structure of layered tellurides is established and it is shown that high applied forces enhance the image contrast in AFM.