People,
The video below might have been posted a few years back, or more like several years back. It is about entrances to underground worlds, not just to the hollow earth.
I heard froma good source that the speaker, Sindoni, was told to cool it, and he stopped with his presentations. There have never been such first class presentations, so that is why, and it is a shame. But click on it and watch it.
Cheers!