National Geographic ChannelNat Geo WildNat Geo PeopleNat Geo People


Find out why one of the most powerful tools of the Second World War was never used.

One of the best-kept secrets of the Second World War was a huge aircraft-carrying submarine designed to deliver Japanese bombers to within a few hundred kilometres of American cities.

Engineers and historians conduct experiments and demonstrations to reveal the secrets behind a technological marvel that could have changed the course of the war.

Plus, archive footage shows what made the I-400 subs so deadly: the three state-of-the-art attack bombers it could carry anywhere in the world. But why was the technology never used in an attack on the US?
Read More

Japan's Secret Sub on Facebook

Get news on your profile
  • Find out more here!

    Celebrated as one of the greatest athletic feats of any kind, Honnold’s climb set the ultimate standard: perfection or death.

  • Big Cat Quiz

    Find out here

    Go on the hunt to determine which aspects of your personality reveal the Big Cat that roars from within.