Active galactic nuclei (AGNs) are among the most luminous mid-infrared (MIR) emitters in the universe. In nearby AGNs, this emission is mostly from warm dust on scales of a tenth to about 10 parsec. This dust surrounds the accretion disk and absorbs its light along half of all lines of sight. While the structure and dynamics of this dust are still largely unknown, it has become clear in recent years that the "torus" picture is too simplistic since the majority of MIR emitting dust is actually located in the outflow direction rather than in the equatorial plane of the AGN. I will summarise the science highlights from AGN observations in the MIR at the highest angular resolution, in particular with long-baseline optical interferometry. I will also discuss the discovery space for future high-resolution studies with VLTI/MATISSE and ELT/METIS.