Millimeter VLBI and Variability in AGN Jets

Millimeter-VLBI images probe as deep as never before the nuclei of AGN. Global 3mm-VLBI where the VLBA is combined with sensitive European stations, gives CLEAN maps of a quality, which never before was so good. VLBI at 147 GHz yields transatlantic fringes for the first time. Now it will become possible to study the relation between jet kinematics and spectral activity with a few ten micro-arcsecond resolution at the shortest wavelengths.