The ocean covers roughly three-fourths of the Earth’s surface, yet 95% of it still remains unexplored. The unknown can leave lots of room for the imagination to fill, which can range from relatively logical to downright bizarre. From what we’ve discovered about the ocean, bizarre isn’t that far off from the truth; the nature of aquatic life ranges from intriguing to mind-boggling. Here are just a few facts about the ocean to send your brain reeling.

 

Undiscovered life: 94% of life on Earth comes from the ocean, and of that percentage, about two-thirds of it remains unidentified. One constant about deep-sea exploration is the discovery of new specimens, which raises more questions about aquatic life rather than solving them. Some of these species include the world’s ugliest fish, a red sea dragon located in the shallows of the Australian coast, a ghost-like octopod, and a “ninja” shark.

 

Underwater lakes and rivers: Strange as it may seem, lakes and rivers exist on the floor of the ocean as they do on dry land. This occurs when seawater seeps into layers of salt, forming a depression on the ocean’s floor. Because the dissolved salt makes the water denser, it settles into the depressions made and creates what’s known as brine pools. Like rivers and lakes on dry land, brine pools have shores and even waves.

 

Underwater waterfalls: As if lakes and rivers were surprising enough, oceans also have underwater waterfalls within them. These are formed when there’s a temperature difference between different sides of the colliding ocean, sending the colder water down while the warm water keeps afloat. The most well-known example of this is also the largest known waterfall on Earth: the Denmark Strait Cataract. The Denmark Strait is over three times the height of Angel Falls in Venezuela, and has about 2,000 times the amount of water as Niagra Falls does at its peak.

Historical artifacts: There are more historical artifacts on the ocean floor than in all of the world’s museums combined, ranging from a Viking sundial to gifts to the gods. It’s estimated that about one million artifacts are buried in the deep, and most of these artifacts have yet to be discovered.