>>40526649The Earth is big. Well, relative to us at least. In the galaxy (let alone the known universe), it’s like a grain of sand on a shoreline or even smaller. But we’re also like a grain of sand to the Earth. All that is to say, don’t underestimate how much could exist under your feet.
Governments and militaries, like of the U.S., have exploited this to create entire DUMBs (Deep Underground Military Bases).
Just as there are those, there are also extensive cave and tunnel systems that can go quite a bit deep underground, also in and under mountains. (I made a similar post about this on /pol/ recently, in the case you find this sounding too familiar.) Naturally occurring or aided by nature, but could definitely be excavated deeper and even terraformed to some extent by a sufficiently technologically advanced civilization.
I believe some aliens have bases there. In fact, the beings known as Reptilians seem to have a big abode there, if you read the Lacerta files. In fact, the claim is even that they were before us an are actually the ones native to the Earth. Or more native than us, at least.
Earth humanity is the result, evidently, of an accelerated simian-evolution project taken on by other extraterrestrial races, perhaps even partially as a race-renewal project for themselves (a similar impulse that drove, say, Old World Europe to expand into and colonize the New World), and something like a cosmic-conservatory project, a zoo or experiment. This could include several different alien races, responsible for our significant genetic variations in the form of race, from East Asians to Africans to Caucasian Whites and Arabs and so forth. Records of this are in lots of myths and religious lore, from Sumerian/Mesopotamian mythology, to the Bible it influenced, to Amerindian legends. The Pleiades show up in this context a lot, and perhaps even more significantly the Sirius star system with Sirius A and B.