Recent developments in spin-polarized scanning tunneling microscopy and spectroscopy have led to an unprecedented insight into magnetism at the nanometer length scale and, in some cases, even down to the atomic level. The correlation between structural, local electronic and local magnetic structure can now be studied beyond the exchange length. Most striking recent results include the discovery of atomically sharp magnetic domain walls in atomic layers of iron and the determination of the intrinsic width of magnetic vortex cores in three-dimensional iron islands. (C) 2003 Elsevier B.V. All rights reserved.