Black holes are objects so massive and compact that not even light can escape from inside them. But just how massive can they get? In this episode of Chasing Starlight we take you on a tour of the most extreme black holes we know of. Note: when we talk about supermassive black holes in the second part of the video, we mention "distances" that correspond in fact to the time it takes the light of those objects to reach us. Due to the expansion of the Universe, the actual distances are larger. Also, note that Gaia BH3 is the most massive stellar black hole in the Milky Way, but there are more massive ones in other galaxies.