Black holes

I give a brief review of some problems of the physics of black holes and discuss important new points. I start from the physics outside the black hole's boundary. But probably the problems of the internal structure achievements in our understanding of the nature of the singularity (and beyond) inside a realistic rotating black hole. This presentation also addresses the following questions: Can we see what happens inside a black hole? Can a falling observer cross the singularity without being crushed? An answer to these questions is probably “yes”. Finally I discuss some problems of black hole astrophysics.