If you followed the Titan submersible story from a few months ago,

you know of the terrifying consequences of going too deep in a submarine.

Well, unfortunately, the Titan submersible is far from the worst incident of its kind.

As always, viewer discretion is advised. I think being afraid of the ocean is one of the fears that's completely justified.

If you ever unlucky enough to find yourself in the middle of one, not only do you have

no way of ever making it to shore, but there are things below you somewhere in the depth

that are just as horrifying as they are dangerous.

Thousands of feet below you, there's nothing but an inhospitable abyss, and it would

only be a matter of time before you could no longer tread water.

That alone is terrifying enough, but incredibly, even if you think you know all of the scary

things that the ocean has to offer, I hate to break it to you,

but there is one that you might not have heard of that is the most terrifying of all.

Take a look at this picture.

This is an image of the Atlantic Ocean that was taken by NASA from orbit.

For those of you just listening, there is a bright blue swirl that kind of looks like a storm

you'd see in the clouds of Jupiter. This is something known as an eddy, and an eddy is a circular current of water that looks like a whirlpool.

Typically these are small and you might notice them while you're paddling a canoe.

However, they are constantly forming in any body of water with a current.

In the Earth's oceans, these can become large enough that they're assigned names similar to hurricanes.

The one in the picture is 150 kilometers across. The reason it's so visible is that it happened

to form in an area with lots of phytoplankton. Now, generally these aren't harmful, but not always.

In 2014, a diesel-electric submarine was on a military mission near the Parasol Islands in the South China Sea.

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