There has been a discovery recently that there is 83 black holes! They are at the end of visible universe. These were observed from a very powerful telescope. Black holes have the capability to swallow planets, stars, and even other back holes. This is a scary thought, but it is so far away, it would probably get here when humans are extinct or we have left the planet. This is because we are talking about the very fringe of what we see of the universe.