Quanta: how do you take a picture of a black hole? (and why the next goal is a movie)

Shep Doeleman explains how the Event Horizon Telescope needed a telescope effectively the size of the Earth, stitching together radio dishes across continents with atomic clocks and hard drives physically flown to correlators. The next goal is to turn still images into a movie of how the gas around the black hole moves. What part of this still blows your mind, the planet-sized baseline, the data logistics, or the fact that it worked at all?