More than 70% of our planet is covered in water, and yet we’ve barely explored what’s hiding beneath its surface. Who knows what strange creatures or other mysteries might be lurking in the depths of our oceans and seas? It’s a pretty terrifying thought, even if you’re someone who loves a good swim.
Below, we’ve rounded up some of the most unnerving photos of different bodies of water that might just trigger your thalassophobia. Scroll down to check them out, and don’t forget to upvote the ones that give you the biggest chills!
#1 Underwater Waterfall
Image source: bnasty1998
#2 Fin Whale Vertebrae Underneath The Freezing Water Near Kongsfjorden In Norway
Image source: [deleted]
#3 Giant Anaconda In The Amazon River
Image source: PostModernPromethius
Thalassophobia is the intense fear of large, deep bodies of water, such as oceans, seas, and lakes. And while plenty of people might feel a little uneasy swimming somewhere they can’t see the bottom, those with thalassophobia can become genuinely terrified by the thought of it.
In fact, even looking at pictures of the ocean can trigger anxiety or panic in some people. So, what exactly makes deep water so frightening?
#4 Dean’s Blue Hole In Long Island, The Bahamas
Image source: pinkblueegreen
#5 Deep Water Swell
Image source: rock-o3000
#6 This Seaweed Through Clear Water
Image source: appealing_orange
Well, there isn’t one single explanation. According to psychologists interviewed by WebMD, thalassophobia can develop after a frightening experience in the water, but it can also be something we learn from other people or even movies.
For some, it’s simply the fear of the unknown. After all, there’s something pretty unsettling about floating above thousands of meters of water without knowing what might be underneath you.
#7 Underwater Shark Statue At Lake Neuchâtel
Image source: 1091drawde
#8 Kayaking With The Giants!
Image source: ilovenyc
#9 The Pacific Ocean
Image source: [deleted]
And the fact that we still know so little about our oceans probably doesn’t help. According to the Seabed 2030 project, only 28.7% of the world’s ocean floor had been mapped to modern standards as of April 2026.
Even more surprisingly, a 2025 study published in Science Advances estimated that humans have visually observed less than 0.001% of the deep seafloor.
#10 Crack In The Ice In Nunavut
Image source: colapepsikinnie
#11 All These Water Spouts Happening At Once
Image source: JAdamsidk123
#12 My Friend Posted This On Her Facebook
Image source: AristonD
Of course, some parts of the ocean are much harder to reach than others. The deepest known point is Challenger Deep, located in the Mariana Trench in the Pacific Ocean, approximately 10,935 meters below the surface.
To put that into perspective, you could fit Mount Everest inside it and still have water above the mountain’s peak. And yes, humans have actually made it all the way down there, although only a small number of people have ever done so.
#13 Free Diving In A Kelp Forest
Image source: mike_pants
#14 Grand Turk 700 Foot Ocean Drop Off
Image source: SaltMill
#15 Terrifying
Image source: Himerly
But what makes these depths especially fascinating is the life that manages to survive there. Far below the surface, sunlight disappears, temperatures drop, and the pressure becomes enormous. Yet plenty of creatures have found ways to live in these conditions.
Take the anglerfish, for example, which uses a glowing lure to attract unsuspecting prey straight toward its mouth. With its sharp teeth and unusual appearance, it looks like something someone dreamed up for a horror movie.
#16 A Howling Abyss
Image source: Equis4
#17 On A Boat But Still Underwater
Image source: alexthehut
#18 Is To Me Or Are Black Tiled Pools Terrifying
Image source: Desperate_Squirrel20
The anglerfish is hardly the only strange creature down there. In fact, scientists estimate that around 90% of animals living in the open ocean below 500 meters can produce their own light.
This ability, called bioluminescence, helps marine animals attract food or communicate with one another. Some even use it to scare away predators. Imagine how incredible it would be to see all those glowing creatures floating around in the darkness.
#19 The Surfer Seems So Small
Image source: Chimp_The_Wingman
#20 First Ever Underwater Photograph By French Photographer Louis Boutan (1893)
Image source: [deleted]
#21 A Large Strawberry Squid
Image source: gayfroggs
Now, if all this talk about mysterious sea creatures has made you even more nervous about swimming, here’s something reassuring. Most of these unusual deep-sea animals live far below the places where people normally swim.
And even sharks, which have a particularly frightening reputation, are much less likely to attack humans than movies might suggest. According to the Florida Museum of Natural History, there were 65 recorded unprovoked shark bites worldwide in 2025. Considering how many people enter the ocean every year, such encounters are relatively rare.
#22 Lumpsucker, Found In The Freezing Waters Of Arctic, North Atlantic, And North Pacific. It Swims At Depths Of 1,700 M (5,600ft)
Image source: Mahmoods
#23 Hairy Crab
Image source: FaffeJaffe
#24 (Oc ) Finding Myself In A Full-Scale Thimble Jellyfish Invasion
Image source: benfreediver
So, while it’s perfectly understandable to feel a little nervous about what might be lurking beneath the waves, there’s also plenty to admire about the underwater world. Scientists are still discovering new things about it, and each expedition gives us a better idea of what life looks like far below the surface.
Of course, knowing more about the ocean doesn’t necessarily make those dark, seemingly bottomless waters any less creepy. And if these photos have convinced you to stick to swimming pools for a while, we certainly wouldn’t blame you.
#25 Orcas In The Waves
Image source: Abesens
#26 The Arch In The Blue Hole, Egypt Which Has Infamously Claimed Up To 200 Lives
Image source: pinkblueegreen
#27 Rebreather Diving, Eastern Slovakia
Image source: AVAN007
#28 My Cousin’s Sister-In-Law Works On A Tugboat Which Tows Oil Platforms Across The Ocean. In All Weather Conditions
Image source: D3qual
#29 Manly Ferry This Morning
Image source: CoopersPaleAle
#30 Pic Of A Leopard Seal
Image source: [deleted]
#31 Black Lined Pools Are A Thing… And They’re Terrifying
Image source: LestrangeLauren
#32 Archaeological Dig Finds And Exposes Whole, 9000-Year-Old Town Swallowed By The Sea
Image source: cardinarium
#33 In The Deep Dark Ocean, You Can’t See What’s Swimming Up Beneath You
Image source: EyesNoEyes__
#34 Going Through Old Pics, Thought I Would Drop This Here
Image source: fancyzoidberg
#35 Today I Figured Out Why I Never Wanna Fall Into Dam Lake. Never
Image source: dafyddtomas
#36 Two Tiny Boats Floating Over An Underwater Cliff
Image source: [deleted]
#37 This Picture I Took From Below The Diving Pier In A Lake Looks Very Eerie
Image source: nderestimatedPower
#38 Ladder To Ocean Depths
Image source: curiousbydesign
#39 Here’s A Photo I Took While In Florida
Image source: [deleted]
#40 I Got Caught In A Storm While Kayaking
Image source: RedDeadVegetation
#41 Take A Swim In This?
Image source: Boottyyjuice
#42 The Stairs To My Nightmares
Image source: TheGhostOfSamHouston
#43 Sunken Ship In Marseille, France
Image source: andreasmaker
#44 Taken On A Recent Diving Trip, Descending Into The Deep
Image source: Westlyndemon
#45 Photo I Took Yesterday At The Surface Of Loch Lomond In Scotland. Made Me Feel Uneasy As Soon As I Saw It
Image source: sedhig
#46 Two Pictures I Took On Vacation On A Small Dock In A Cave. Every Minute Or So A Big Wave Comes In And Gets Your Legs Wet Up To Your Knees
Image source: Dragneel
#47 Went To A Restaurant By The River, And I Think The Catfish Were A Little Hungry
Image source: AdmiralTyrant
#48 My View At Work Today
Image source: Gabriel-smari
#49 Sinking Boat Off Of Marathon Key, FL
Image source: frieswiddat
#50 I Was Having So Much Fun I Forgot How Far From Our Airbnb Island I Wandered
Image source: MrMalta
#51 Look Close
Image source: sjsharks8
#52 There’s Death For You In The Deep Dark
Image source: Trish_the_dish
#53 Deep Sea Eel
Image source: Neuraxis
#54 [oc] I Think Something Just Touched My Leg
Image source: WolfPaws123
#55 This Creature Was Newly Discovered In New Zealand. Been Trying To Find What It’s Called But No Luck
Image source: Suspicious-Beat-6204
#56 My Favorite Jellyfish, The Stygiomedusa Gigantea, A Very Illusive Creature Only Spotted Over 100 Times In The Last 100 Years :)
Image source: IrulanTheArtist9504
#57 Faceless Cusk Eel, Found At Depths Of 16,000 Ft, Is Named After Its Appearance Due To Having An Extremely Reduced “Face”
Image source: AventusW
#58 This Gives Me A Vague Feeling Of Thalassophobia
Image source: Imaginary-Reading-63
#59 Submerged Trees/Tree Stumps Gave Me A Very Creepy Feeling When Kayaking On This Lake
Image source: TheCivilEngineer
#60 Not The Best Start To A Fishing Trip
Image source: DreamCheeky
#61 Abandoned Silver Mine Shafts. Lake Superior Thunder Bay Ontario
Image source: Mooky7
#62 Sitting In The Engine Of A Sunken L-1011
Image source: 77xp
#63 A Flooded, Abandoned Mineshaft. I Asked The Fb User, Than Took This Picture, His Permission To Post
Image source: Good-Bloke
#64 My Friend Took This Photo From The Fishing Boat She Works On In Antarctica
Image source: fuqers
#65 A Pool With Holes
Image source: Geschinta
#66 Lumberton, TX 9/3/17
Image source: FilthyFilthFilth
#67 Taking A Short Break While Doing Hull Inspections
Image source: TheDoctor_RS
#68 Aft Ballast Tank On My Ship. Had To Dewater And Inspect It
Image source: Cornholiolio73
#69 131 Ft Deep Swimming Pool In Padua, Italy. That “Landing Pad” At The Bottom Especially Freaks Me Out
Image source: jennasky
#70 “Thalassophobia” 3D Render
Image source: AnarkyMusic
#71 The Eye Of S(E)auron
Image source: cuebas
#72 Underwater Path. Magical Zakynthos Caves, Greece
Image source: kinkykat977
#73 Because All My Friends Say This Photo Of Me Freediving Gives Them The Willies
Image source: marinemik
#74 The Image That Started It All
Image source: wmszeligaSfghr4567
#75 Brine Pools Are Just The Scariest Thing
Image source: DedotadedWham
#76 Walked About 30 Minutes Out During Low Tide To Read This!
Image source: ChaeusXCVI
#77 This Is An Under-Ice Observation Tube In Mcmurdo Station, Antarctica
Image source: [deleted]
#78 This Grounded Ship Looking Like A Giant Meg
Image source: roncastelino
#79 It’s A Nice Peaceful Day Until You Get A Glimpse Of What Lies Beneath
Image source: Desperate_Squirrel20
#80 Could You Live Like This?
Image source: sugarvenom697
#81 A Warning Sign For Scuba Divers Deep Underwater
Image source: raewlaydkxn018
#82 Within The Waves
Image source: FifenC0ugar
#83 Posted On R/Damnthatsinteresting But Thought It Fit Better Here
Image source: [deleted]
#84 Submerged Park Bench
Image source: _ForestDragons_
#85 Not Sure If This Qualifies, But This Picture Is The Cause Of The Worst Nightmare I’ve Ever Had
Image source: OnTheOctopusRide
#86 There Is Something Big Down There … I Can See It’s Shadow
Image source: Scuba-Life
#87 I Don’t Like This Picture
Image source: xdcutemynutella
#88 Don’t Get Stranded… Off The Coast Of Malta
Image source: TheBeadGeeks
#89 Aitoliko Village In Greece
Image source: Public_Individual823
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