The Event Horizon in General Relativity

You can take a picture of a black hole and we've done it. We have a couple of really cool images and you can see a ring of gas around it. And then at the center, you see an area that isn't emitting any light. What I'm saying is that, mathematically speaking, or most technically in general relativity, the region around the black hole that we call the event horizon is something you can only ever determine sort of like in the infinite future of the universe. Even if you're looking at the black hole and you see no light emitted from it, that doesn't mean that there isn't some path for a photon to like graze just within it and eventually