How it started / How it's going
A paper by Falcke, Melia, and Agol appeared in The Astrophysical Journal #OTD in 1999, arguing it might be feasible to image the shadow of a distant supermassive black hole using Very Long Baseline Interferometry.
Over the last few years, the Event Horizon Telescope has imaged the shadows of supermassive black holes at the center of M87 and our own Milky Way.
Images: EHT Collaboration.