From: Talks with Ramana - 23rd January, 1936

Mr Paul Brunton asked Sri Bhagavan if the Hill here is hollow.
(i.e. Arunachala hill where Ramana lived)

M.  The puranas say so.  When it is said that the Heart is a cavity, penetration into it proves to be an expanse of light.  Similarly the Hill is one of light. The caves, etc. are covered up by that Light.

PB: Are there caves inside?

M: In visions, I have seen caves, cities with streets, etc. and a whole world in it….

M:  You yourself have seen hermitages, etc. on this Hill in a vision.  You have described such in your book (Search in Secret India).

PB:  Yes. It was on the surface of the Hill. The vision was within me.