ELI5: Explain Like I'm 5

I-400 class submarine

An i-400 class submarine is a really big underwater machine that can go really deep into the ocean. It is like a big, long tube that can hold lots of people and equipment.

The i-400 submarine was built a long time ago, during World War II. It was made by the Japanese, who wanted to use it to take secret missions to other countries. They wanted to surprise their enemies by launching attacks from underwater where they couldn't be seen.

The i-400 submarine was so big that it could fit three smaller planes inside it! Yes, you read that right, THREE planes! The planes were small enough to fold up and be stored in the submarine's belly like a toy car in its box. When the submarine wanted to launch the planes, it would surface and the planes would fly out like birds from a nest.

The i-400 submarine was also very advanced for its time. It had lots of special features that made it harder for enemies to detect it. For example, it could travel underwater for a long time without being detected and it was really quiet, which meant that other ships and submarines couldn't hear it coming.

Today, the i-400 submarine is no longer used because it is old and outdated. But it is still really cool to learn about because it was such an innovative machine for its time!
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