• A. The Atlantic Ocean
  • B. The Indian Ocean
  • C. The Pacific Ocean
  • D. The Arctic Ocean

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Think of the world’s largest ocean - that enormous body of water that covers nearly a third of our planet’s surface and borders Asia, Australia, and the Americas on all sides.

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The correct answer is C. The Pacific Ocean.

The Pacific Ocean contains the deepest point on Earth: the Mariana Trench. The very deepest spot, the Challenger Deep, lies about 10,994 meters below sea level. To give you an idea of how deep that is: you could completely submerge Mount Everest (8,849 meters) in it, and there would still be over 2 kilometers of water above the summit. Let that sink in.

And the pressure down there? Approximately 1,086 bar. That’s like having about 50 jumbo jets pressing down on your thumb. Doesn’t sound pleasant, does it? But here’s the weird thing: creatures actually do live at that depth. Special fish species, amphipods, bacteria - all perfectly adapted to this extreme world where not a single ray of sunlight reaches.

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The Mariana Trench is located in the western part of the Pacific Ocean, somewhere east of the Mariana Islands and about 200 kilometers southwest of Guam. It was formed by the Pacific Plate sliding beneath the smaller Mariana Plate - geologists call this subduction. Essentially, the Earth is kind of eating itself there.

Almost no one has ever been down there. In 1960, Jacques Piccard and Don Walsh did it for the first time in the bathyscaphe Trieste. They hung around at the bottom for about 20 minutes. After that, it wasn’t until 2012 that James Cameron (yes, the Titanic and Avatar guy) made the descent as the third person in his specially designed submersible, the Deepsea Challenger. He filmed there for over three hours for a documentary.

What they found there was quite shocking. In 2019, an expedition encountered plastic waste at the bottom of the Challenger Deep. So even the most remote spot on Earth isn’t safe from our trash. But there was also good news: they discovered new fish species thriving there in total darkness and under insane pressure.

Oh, and here’s another fun fact: the Pacific Ocean is not only the deepest but also by far the largest ocean. At approximately 165 million square kilometers, it’s bigger than all the land masses combined. The name “Pacific Ocean” comes from Ferdinand Magellan, who encountered calm weather during his crossing in 1520. A bit ironic when you consider this is the ocean with the most typhoons and tsunamis.

The deep sea actually still remains one big mystery. We’ve mapped an estimated less than 20% of the ocean floor. Much of what we do know has only been discovered in the last few decades thanks to robotic submersibles and advanced sonar technology. Pretty crazy actually: we know more about the surface of the moon than about what’s happening underwater on our own planet.