The image was produced by the Event Horizon Telescope, a network of 10 radio telescopes spread across the planet and functioning as if it were a single receiver, one tuned to high-frequency radio waves. It represents a technical triumph for the scientists involved, and inaugurates a new era in the study of black holes, galaxy formation, and the laws of physics under extreme conditions.
The M87 black hole appears as a dark shadow within a doughnut-like ring of hot, glowing material.
I thought this video about the black hole was fantastic.