- Secret New Mexico base is built to withstand a nuclear attack
- It reportedly holds the original texts of Scientology founder L Ron Hubbard
- Scientologists reportedly believe in sinister extraterrestrial emperor Xenu
- But church leaders routinely deny this or any talk of aliens
- BBC reporter John Sweeney investigated site for new book
The religion, which believes a sinister extraterrestrial being called Xenu brought billions of people to earth in spaceships similar to DC8 airliners, operates a giant underground base hidden deep within the New Mexico desert.
BBC reporter John Sweeney, who famously clashed with Scientologists during a Panorama report in 2007, travelled to the site dubbed Scientology's 'alien space cathedral', to research a new book