This colloquium will tell three stories about what happens inside astronomical black holes. The first story is about the simplest kind of black hole, a non-rotating Schwarzschild black hole. I show that the singularity is a surface, not a point, and I show that Hawking radiation diverges near the singular surface. The second story is about rotating black holes. A rotating black hole has an inner horizon where there is a (Penrose-Poisson-Israel) instability, which I call the black hole particle accelerator, which is the most violent instability in the Universe, including the Big Bang. I show that the instability gives way to complicated oscillatory (Belinskii-Khalatnikov-Lifshitz) collapse. The third story is the most fantastic. You will have to attend the colloquium to hear it.