25 Bizarre Deep Sea Anomalies That Can’t Be Explained

Posted by , Updated on May 23, 2024

The vast depths of the ocean are home to numerous unexplainable mysteries. This is not surprising, given that vast portions of seas, lakes, and other bodies of water remain unmapped, full of undiscovered secrets. The deep-sea environment produces strange sounds and houses enigmatic marine life, presenting even the most astute scientists with numerous unresolved questions despite their ongoing discoveries. Indeed, it is a world filled with conundrums and oddities! Get ready to be amazed as we explore 25 of the most perplexing Deep Sea Anomalies That Remain Unexplained.



Four Submarine Disappearances of 1968

uss scorpionSource: http://www.historynet.com/the-uss-scorpion-buried-at-sea.htm

In 1968, four submarines from different countries mysteriously disappeared. They were USS Scorpion, INS Dakar, French Submarine Minerve, and Soviet K-129. Reasons behind their disappearances remain shrouded in mystery with several theories including secret attacks from the Soviets and design flaws.


Cannibal Shark in Australia

great white sharkSource: http://www.iflscience.com/plants-and-animals/massive-sea-creature-attacks-kills-and-eats-3-meter-long-great-white-shark/

Australian scientists reported a strange anomaly about one of their tagged 9-foot-long great white sharks. Called “Shark Alpha,” their shark tag ended up washing up on shore four months after they tagged the shark. The data suggested some unknown creature ate the shark. They assumed it was a cannibal great white shark, but they aren’t for certain.


Sycamore Knoll

sycamore knollSource: https://www.huffingtonpost.com/2014/06/19/malibu-underwater-alien-base_n_5493186.html

Called the “Sycamore Knoll,” this anomaly was discovered using Google Earth. It’s 2,000 feet below the surface of the water and looks like a Greek structure with several pillars. While UFOlogists believe it’s the holy grail of discoveries, geologists didn’t think much was special about it. The coordinates are 34° 1’23.31″N 118° 59’45.64″W.


Atlantis of Japan

yonaguniSource: https://www.thesun.co.uk/living/2816443/these-incredible-underwater-ruins-are-known-as-japans-atlantis-and-people-think-they-could-be-proof-of-alien-life/

In Japan, when divers went looking for hammerhead sharks, they found something else. At around 490 feet by 130 feet and 90 feet high, a monument or ancient structure sat beneath the water. Since its discovery, scholars have argued about its creation, some saying it was naturally made, while others thinking it was man-made. Those who say it’s man-made claim the site is over 9,000 years old and submerged underwater due to tectonic activity.


Baikal Lake

lake baikalSource: http://mysteriousuniverse.org/2014/12/the-deep-mysteries-of-the-worlds-deepest-lake/

Up in the northern part of Siberia, Russia, this lake is one of the oldest known in the world, dated at 25 million years old. Many mysteries surround this lake, including a creature the native people call Lusud-Khan which translates as Water Dragon Master. Early Chinese explorers and even modern fishermen have reported sightings of this sea creature. In addition, a stone slab dating back to the 3rd and 9th century BCE depicts a mysterious water creature.


Milky Sea Phenomenon

milky sea phenomSource: https://science.howstuffworks.com/environmental/earth/oceanography/milky-sea1.htm

For years, sailors have mentioned the Milky Sea Phenomenon, describing it as pale, milky, glowing waters stretching for as far as the eye can see. Scientists chalked it up to a tall tale until 1995 when the S.S. Lima recorded it happening. While they’ve figured out it’s the gathering of luminous bacteria, they’re not sure why they gather in large numbers in the first place.



upsweepSource: https://www.theepochtimes.com/strange-sounds-in-the-ocean-source-unknown-listen-here_901892.html

Scientists first discovered a sound in 1991 that isn’t whales or ship vibrations. They called it “Upsweep,” and it’s mystified them for decades. It’s been detected from one end of the Pacific to the other. While they hypothesize it’s the sound of seawater coming into contact with lava, they are not certain.


Ocean X

baltic seaSource: https://www.express.co.uk/news/science/750245/baltic-sea-anomaly-crashed-ufo-seabed-ocean-x-peter-lindberg

Discovered by Swedish explorer Peter Lindberg and his Ocean X team, the Baltic Sea Anomaly is a Millenium Falcon-looking structure that could be 140,000 years old. It looks like a huge rock, but some believe it’s made of metal and could be an extraterrestrial crash site.


Legendary Lost City Of Heracleion

heracleionSource: https://www.atlasobscura.com/places/the-lost-city-of-heracleion

Off the coast of Alexandria, researchers exhumed a lost and ancient city called Heracleion. Several ruins, statues, and artifacts were found, including gold coins and a temple of the god Amun-Gereb. It has an obscure history, and no one knows how it ended up underwater.


Mound in the Sea of Galilee

sea of galileeSource: https://www.cnn.com/2013/04/19/world/meast/israel-ancient-structure-mystery/index.html

Submerged about 30 feet (9 meters) under the Sea of Galilee is a mysterious circular structure that scientists can’t explain. It’s made from basalt rocks and in the form of a cone. Some believe the water was lower in ancient times, and the cone could have been an important monument.


Lake Vostok

vostokSource: http://www.sciencemag.org/news/2013/07/what-s-really-going-lake-vostok

Buried 4,000 meters below Antarctic ice, this lake was confirmed to exist in 1993 thanks to satellite-based radar. Since it has been untouched by the outside world for so long, many speculate if it has prehistoric life forms, fossils, or other clues to Earth’s past. There’s even a possibility fish live in the lake. No one really knows for sure.


Structure in Lake Macdonald, Ontario

MacDonaldSource: http://www.prweb.com/releases/2008/03/prweb739524.htm, https://www.ancient-code.com/10000-year-old-underwater-structures-at-lake-macdonald-point-to-a-long-lost-civilization/

About 40 feet (12 meters) below the surface of Lake MacDonald in Ontario, Canada, lies a giant boulder on top of several baseball-sized stones. The larger rock is roughly 1,000 pounds (453 kg). Originally, geologists thought it was naturally made, but upon further inspection, they realized it was likely man-made. Who made it and why remains a mystery.


Cuba’s Underwater City

cuban citySource: https://news.nationalgeographic.com/news/2002/05/0528_020528_sunkencities.html

Off Cuba’s coast in the waters of Cabo de San Antonio, scientists have discovered unusual formations of smooth blocks, crests, and geometric shapes. The structures are under about 2,500 feet (750 meters) of water. Scientists examining the site believe it’s difficult to explain the structures from a geological standpoint.


Lake Michigan’s Stonehenge

lake michiganSource: http://www.collective-evolution.com/2015/12/24/are-these-remnants-of-a-9000-year-old-stonehenge-at-the-bottom-of-lake-michigan/

In 2007, a professor of underwater archaeology at Northwestern Michigan University College discovered a weird formation of rocks underneath the surface of Lake Michigan. Most of the lake bed is entirely empty except for these rocks lining up almost perfectly. After exhuming one of the rocks, scientists believe one of them had a petroglyph of a mastodon carved into it.


The Whistle

underwater whistleSource: http://mentalfloss.com/article/62731/9-strange-sounds-no-one-can-explain

In 1997, researchers at the National Oceanic and Atmospheric Administration discovered a low whistle noise. Both the location and source are unknown.


Bimini Road

Bimini_islandSource: http://www.ancient-origins.net/myths-legends/does-bimini-road-lead-lost-civilization-atlantis-002070

Off the coast of Bimini in the Bahamas is a stone structure underneath the water that looks eerily like a road. Scientists visited the site and studied the site. While some say it’s possible it was formed naturally, others aren’t so sure. Many believe it could be a lost city or even the lost city of Atlantis.


Gulf of Khambhat Discovery

Gulf_of_KhambhatandGulf_of_KhambhatandSource: http://news.bbc.co.uk/2/hi/south_asia/1768109.stm

In 2002, off the coast of India, marine scientists discovered archaeological remains they said could be part of a long lost civilization over 9,000 years old. If true, it predates the oldest known structures by 5,000 years, totally rewriting history.


Lost Locomotives

old trainsSource: http://whatculture.com/science/7-most-bizarre-underwater-discoveries-nobody-can-explain?page=4

In 1985, while Captain Paul Hepler scanned the New Jersey ocean floor on his vessel, the Venture III, he discovered several unusual objects. Turns out, he found some of the oldest trains in American history. Little is known, however, about their origins or how they ended up at the bottom of the sea.


Wilkes Island

antarcticaSource: https://www.thesun.co.uk/tech/2580013/mysterious-giant-staircase-spotted-in-the-frozen-wastes-of-antarctica/

Using Google Earth, investigators spotted what looks like a large staircase on the Antarctic location of Wilkes Island. Since its discovery, speculation has abounded about its origins and purpose. The most reasonable of theories suggest it’s an impact crater. Others, however, have gone so far as to say it’s an old Nazi base or a UFO site.


Circular Anomalies

circlesSource: https://listverse.com/2013/05/20/10-mysterious-underwater-anomalies/

Off of the coast of Florida, North Carolina, and Belize, investigators have discovered circular objects on Google Earth. Some have noted they could be ancient stone structures similar to those found in Saudi Arabia. If so, the underwater structures would be better preserved than those on land.



juliaSource: http://mentalfloss.com/article/62731/9-strange-sounds-no-one-can-explain

Recorded in 1999, the sound called “Julia” lasted for roughly fifteen seconds before it disappeared. Heard by the Equatorial Pacific Ocean hydrophone array, some think it might have been an iceberg.


Slow Down

Slow_DownSource: http://mentalfloss.com/article/62731/9-strange-sounds-no-one-can-explain

Recorded on May 19, 1997, the sound lasted around seven minutes before decreasing in frequency. Some think it could be a giant squid, while others point to the source as an iceberg. The sound has been heard on several occasions.


Purple Orb

purple orbSource: https://www.rd.com/culture/ocean-mysteries/

Researchers of the Ocean Exploration Trust discovered a bizarre purple orb at the bottom of the Pacific Ocean near California. While the scientists joked it was a spider egg or a tiny octopus, the latest research indicates it might be a velutinid, a type of snail.


The Disappearing Island of Bermeja

BermejaSource: http://www.realclear.com/offbeat/2015/12/28/so_what_did_the_cia_really_do_to_the_disappearing_island_12592.html

For hundreds of years, the island of Bermeja could easily be found in the Gulf of Mexico near the Yucatan Peninsula. However, now all that’s found in that location is water, suggesting it disappeared, but no one really knows where it went. When Mexican officials researched the location of the island, they found no evidence it ever existed at all, questioning the old maps that said it did. Many theories exist about its location, including a conspiracy by the CIA to make it disappear to the possibility that it never existed in the first place.


Whales Singing Deeper

blue whaleSource: https://www.nytimes.com/2008/07/29/science/29whale.html

Blue whale singing is usually intended to attract a mate, and over the past forty years, over seven different blue whale populations have been recorded singing at a deeper frequency than before. Scientists don’t understand why. Some think it could be related to population density and competition.

Photo: Featured Image - Vincent Lou from Shanghai, China, Yonaguni Monument DSC02854 (12737275763), CC BY 2.0 , 1. "Mike" Michael L. Baird, Blue Whale (Balaenoptera musculus) Mysticeti baleen whale, CC BY 2.0 , 2. WikipediaCommons.com (Public Domain), 3. Ryan McMinds, E6.17.Orb.annu.1.20150523 (20284884840), CC BY 2.0 , 4. WikipediaCommons.com (Public Domain), 5. WikipediaCommons.com (Public Domain), 6. Pixabay.com (Public Domain), 7. WikipediaCommons.com (Public Domain), 8. Ben Brooksbank, Dodworth, Barnsley Westbound coal train on Worsborough Incline, with two banking engines geograph-2761844-by-Ben-Brooksbank, CC BY-SA 2.0 , 9. WikipediaCommons.com (Public Domain), 10. WikipediaCommons.com (Public Domain), 11. WikipediaCommons.com (Public Domain), 12. Cody.Pope, Lake Michigan HDR Sunset, CC BY-SA 2.5 , 13. Todd Murray from Bloomington, MN, USA, Neptune memorial reef 05, CC BY-SA 2.0 , 14. WikipediaCommons.com (Public Domain), 15. WikipediaCommons.com (Public Domain), 16. gugganij, Sea of Galilee Tiberias Ginosar 200704, CC BY-SA 3.0 , 17. ChrisO (talk), Nile Delta - Naucratis, CC BY-SA 3.0 , 18. Created by Wiki user NormanEinstein, Baltic Sea map Usedom location, CC BY-SA 3.0 , 19. WikipediaCommons.com (Public Domain), 20. Pexels.com (Public Domain), 21. Octagon, Angara-Lake Baikal 1, CC BY 3.0 , 22. Vincent Lou from Shanghai, China, Yonaguni Monument DSC02864 (12737595694), CC BY 2.0 , 23. GoogleEarth.com (Screenshot) (Fair Use: Illustrative Purposes Only), 24. Hermanus Backpackers, Great white shark south africa, CC BY 2.0 , 25. WikipediaCommons.com (Public Domain)