What's special about the Event Horizon Telescope that imaged the M87* black hole?

The video discusses the imaging of the M87 black hole, comparing it to Sagittarius A* in our galaxy. It explains how black holes are measured by their event horizons and why the Event Horizon Telescope is more effective than Hubble for this purpose. The video also covers the challenges of observing black holes due to their lack of light emission and the importance of using various wavelengths. Finally, it explains why M87 star was chosen for imaging over Sagittarius A* due to its larger size and higher activity.

What new insight or understanding did you gain from this video?