Watch Trailer
Watch Sworn to Secrecy: Secrets of War Season 4 Episode 9 Online
-
- COUNTRIES: United States of America,South Korea,United Kingdom,France,Germany,Russia,Vietnam
- Subtitles: English
From silent one-man midget subs to U-boats on secret missions, both sides used secret submersibles of all shapes and sizes to conduct clandestine warfare in the war.
