Hollow Earth - Part Five: The U-209 Letter The biggest cover up ever!!, the Hollow Earth Theory. In this series i will try to unravel all the mysteries concerning this amazing topic. I will cover several rumors that are linked to the Hollow Earth theory, like the Nazi and Reptillian connection. So, sit back and enjoy the Fifth chapter of my Hollow Earth series. Music and video is the Legal property of TheMusicmemorylane. Music created with Magix Music Maker 3, created with Copyright free VTS Files. Produced in The Netherlands. Also visit my Google+ community: 'Locktite1000's Alien and UFO Research Community'