Except that there is not volcanic rock in the area and the one has a cover that is pretty obviously manufactured. The likelyhood of something naturally forming into that shape and in that position is just about zero. Theories run wild. I have seen A) Secret American Base, B) Secret Soviet or Russian Base, C) Secret Chinese base, D) Abandoned Nazi base, E) UFO base (ancient or current), and the wildest of all, F) there apparently is a "Hollow Earth" theory that states that the earth is hollow and that there is a vast civilization in there.
