Is There a Real Black Hole in the Universe?

For black holes, it's all about the density of matter because gravity gets stronger the closer you get to it. We have a model from general relativity that predicts that this would happen. It says, if you get matter dense enough, then you should create this event horizon and have a singularity on the inside. For a long time, that was just theoretical. But then we saw these things out in the universe. And specifically what we saw were very dark portions of space that had a lot of curvature to them,. The only thing left was a general relativity black hole.