The first black hole ever imaged by the Event Horizon Telescope was M87*.
M87* is the supermassive black hole at the centre of Messier 87, a giant elliptical galaxy about 55 million light-years from Earth. The Event Horizon Telescope, or EHT, released its image on 10 April 2019. The image showed a bright, uneven ring of glowing plasma around a dark central shadow.
That dark region is not a photograph of the singularity. It is the black-hole shadow, produced when gravity bends light and some photons are captured. The glowing ring comes from extremely hot gas orbiting near the event horizon.
M87* was imaged before Sagittarius A*, the Milky Way’s central black hole, because M87* is larger and comparatively less affected by rapid changes in its surrounding gas. Its mass is about 6.5 billion times the Sun’s mass, making its apparent structure easier to resolve despite its greater distance.