A black hole is not really a "hole".
A black hole is a celestial body left over from a giant star that has died where its gravity becomes so great that the curvature of space is very steep, resulting in no matter whatsoever being able to escape its gravity when it gets too close, even light.
Black holes are not like this:
Or this.
A black hole is more like this:
Or like this:
So, instead of a hole, a black hole is a black, three-dimensional object with extraordinary density.
And, if asked "where does a black hole lead" then in this context it is the center of the black hole. What is at the center of a black hole? Experts agree to call this unknown region the singularity .
Previously, black holes had an area called the event horizon, which is the boundary where something is no longer possible to escape from the black hole. In the middle of the boundary in the event horizon is called a singularity, which is a place where mass or density becomes infinite and the curvature of space-time becomes infinite too, because gravity is so strong there.
What happens if someone goes in there?
Gone… and never to return.
At least that's what we expect, because we don't have any data yet on what and how the singularity is filled.
