This is an awesome article on black holes!
See, black holes are very, very, interesting, very, very, little thingssssssss. Black holes might be the entrance to another universe, but enough of that (=more of that later!) or they could be a portal to another part of the universe. The universe is four dimensional (last post) and it’s kind of like an oval: if you keep on traveling in a straight line, space-time will actually bend so you will, essentially, after billions and billions of years, end up where you started. So, a black hole is essentially a tunnel, or rip between both sides.