During the past year, significant advances have been made in the characterization of low-dimensional magnetic structures down to the atomic length scale. Spin-polarized scanning tunneling spectroscopy and magnetic force microscopy under ultrahigh vacuum conditions have been applied to image the nanomagnetic domain structure of ultrathin transition and rare-earth metal films, whereas conventional scanning tunneling spectroscopy has been used to study Kondo scattering at single magnetic impurities. The fabrication of artificial magnetic nanostructures using atomic manipulation processes based on the scanning tunneling microscope will additionally allow fundamental investigations of magnetic interactions at the atomic level.