CLASSIC: Are there any real underwater military bases?

We've all seen the space-age secret bases in science fiction and blockbuster films, but could a government or corporation really build a secret, permanent deep-sea base? Where would they do it? Why? Join the guys as they dive into (get it?) the murky world of militaries beneath the waves. They don't want you to read our book.: https://static.macmillan.com/static/fib/stuff-you-should-read/ See omnystudio.com/listener for privacy information.