The Mariana Trench: Earth's Deepest
The ocean, a vast and deep place, even human understanding of the ocean is less than what we have discovered on the moon, and the number of people who have set foot in the deepest place on earth is also fewer than the number of people who set foot on the moon. Back in the 19th century, people did not know much about the ocean, what people imagined about the deep sea were fantasy stories like monsters, shipwrecks, and a completely different civilization existing alongside humans. It is believed that living creatures cannot survive in the deep ocean because people at that time were not really advanced in science and technology, and did not have modern equipment to support deep diving and exploration. So what people observe is just a mysterious black color at the bottom of the deep ocean, and it's all just guesswork, even though you see curious people always wanting to explore the ocean.