Exploring the depths via scuba or free diving is one of those things that seems really cool in theory. Then you swim around in a pool for 36 hours, go to the man-made lake you heard had a flooded town and discover a bunch of muddy brick foundations. It turns out that lakes in the Midwest are about as full of adventurous treasures as the towns around them. But, like the 28 percent of the Earth that's not covered in water, if you pick the right spot at the right time of day, you can find stuff down there that will blow your mind. For instance ...
#5. Underwater Rivers and Deep Sea Lakes (With Waves)
A group of amateur cave explorers discovered a river in Mexico with banks, trees and leaves just like an ordinary river, but with an additional metric shit ton of "WTF," because they were hovering 25 feet over it in scuba gear when they discovered it.
"We're calling it the Meta-River."
While underwater water doesn't seem possible, the "river" is actually a briny mix of salt water and hydrogen sulfide. It's much more dense than regular salt water, so it sinks to the bottom and forms a distinct separation that acts and flows like a river.
In addition to giving scuba divers the distinct feeling that they're flying through a landscape painting, the underwater river allows them to snap mind-blowing pictures like the series you're looking at taken by Anatoly Beloshchin.
Presumably not as entertaining to any fish that happened to be swimming by.
Unfortunately, hydrogen sulfide is extremely toxic, so the chances of the above scuba diver pulling in some sort of meta-fish aren't great. However, there is an underwater body of water on the abyssal plain (the part out past the continental shelf where the ocean floor starts to make shit real) that is teeming with life. Deep sea lakes look like normal lakes, complete with sandy and rocky shores. Scientist call these lakes "cold seeps," but they're a hotbed for life, because apparently waterfront real estate is a hot commodity under water, too. The "rocky" shores are actually made up of hundreds of thousands of mussels.
Blue Earth via Youtube
Pictured: Mussel Beach on the Goo Lagoon.
Even weirder, the lakes under the waves have waves of their own. Check out this video of scientists discovering the waves for the first time if you want to see something cool and hear what it sounds like when scientists lose their shit.
#4. The Ocean's Answer to the Sarlacc
You've likely seen aerial shots of these dark blue holes and assumed there was something down there accounting for the darkness. Maybe some silt or seaweed that's collected in a crater on the sea floor. In fact, those are giant sinkholes in the middle of the ocean that formed during the Ice Age the same way giant city-block-sized sinkholes form in cities today: water, chemicals, time and bureaucratic mismanagement.
This is a sign you might not live in a particularly well-run municipality.
Of course, it's not totally fair to compare it to the Guatemala sinkhole that swallowed an entire city block, since it's bigger and three times deeper than that. Notice that sharp contrast from bright aquamarine to deep dark blue? That's not caused by anything dark trapped in the sinkhole. It isn't caused by anything. It's hundreds of feet of absolutely nothing but cold water straight down to whatever is below the bottom of the ocean until presumably it starts warming up as you near the center of the earth.
Above: Goatse via Poseidon.
If you're the sort of person who immediately wants to know what the craziest goddamned thing you can do to a 600-foot ocean bottom sinkhole is, world free diving champion Guillaume Nery has you covered. He stood on the edge of the world's deepest blue hole without any sort of breathing apparatus, ignored every fiber of his being telling him he was perched on the mouth of a sarlacc and decided he wanted to touch the drain in the ocean's deep end.
Guillaume Nery, Youtube
Because fuck air.
And it only gets eerier inside the hole, where you're forced to face the reality that you've stumbled into either a) the lair of something terrible that is going to swim by overhead and blot out the last trace of sunlight you'll ever see or b) the stomach of some sort of ocean bottom Venus flytrap designed specifically to trap and digest people who see something beautiful and feel the desire to swim down its throat.
Jenny Huang, Dive Photo Guide
When the bubbles get to the surface, it knows to swallow.
In fact, underwater seems like the one place on earth you'd actually be safe from all this horror, but you'd be wrong. And no, we don't mean spider crabs or any other sea creature that looks like a spider. We mean actual air-breathing spiders that spend as much of their lives underwater as whales and dolphins. And they do it using scuba gear that they presumably paid for with their winnings from the face hugger look-alike competition:
Heidi & Hans-Jurgen Koch
We have a new winner in the category of worst thing to see while opening your eyes underwater in a lake.
You had a great run, skinny-dipping cousin sneaking a poop.
The diving bell spider is the only spider on earth that spends almost its entire life underwater. It weaves a special bell-shaped web that catches and contains air bubbles that it brings down from the surface. The web acts like a fish's gills and filters oxygen out of the water around it, so the spider can stay under for a day or more at a time before needing to get more bubbles. It carries the bubbles down to its web by trapping them in hairs on its abdomen, as seen in this not at all terrifying picture from the New York Times:
The New York Times
Welcome to your new life hoping that was a crab that just scampered over your foot.
The spider then takes this air bubble and transfers it over to its web, where it can lie in wait for its prey, avoiding the predatory birds above the water's surface and any pockets of your nightmares that used to be spider-free.
"Ma'am? The spiders are coming from inside your lungs."
Here's a video of one bringing the bubbles down before finally climbing inside and beginning to devour a freshly caught snack.
The female diving bell spiders often construct much larger webs so that they can house their eggs.
"We also like to store them in your ears. While you sleep."
And now you get to worry that the squishy thing you just stepped on was a nest of hatching spiders.