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.
Welcome to earth: The huge symbol etched into the desert in New Mexico next to the Scientology base dubbed the 'alien space cathedral'
