Anomalous Underground Humming in Portugal

The undeground 'humming' anomaly is pretty old. Reminds me of a story I read in one of my many books on the Esoteric. Apparently there was a humming in Tunguska some 50 or so years ago, and upon investigation, a giant black, polished stone door was found in a cave and behind the door was the loud roar of machinery. According to the discoverers, this was the cause of the Tunguska event. A giant machine that emitted a ray of some sort and was basically all leading back to some even older story regarding how the earth was (artificially) terraformed and to keep it in the position it is in orbit, a giant machine was built into its core. Sounds far-fetched I know...but I swear I read it.