Every other day a preprint appears on arxiv, in the gr-qc section, that discusses what happens when an observer crosses a black hole horizon, and how he arrives at the singularity. All these papers are written by people who believe that space is continuous, and that it can be extended beyond the horizon. Sadly, this nonsense is even found in many books. But it remains nonsense. Space and space-time cannot be extended beyond the horizon, because they are not continuous. Speaking about "beyond the horizon" is like counting angels. There are no angels. But angels have been classified, it might be said: after all, there are seraphim, and cherubim, and many others, and several angles are known by name, such as Gabriel and Raphael. Despite all this, angels are a delusion. Neither is it possible to cross the horizon or hit a singularity; that is a delusion.
There are people getting their PhD on angiology, and there are people getting their PhD on what happens beyond black hole horizons. The value of the work is the same.