Liciana Q 
Explore the fascinating mysteries of the ocean, from underwater monuments to strange ocean sounds, that continue to fascinate and baffle scientists today.
The ocean, which covers more than 70% of the earth’s surface, still holds many secrets that have yet to be revealed.
In the darkness and incredible depths, there are strange phenomena that confuse scientists and researchers. Here are 10 of the ocean’s greatest mysteries that continue to captivate the world’s attention.
1. Yonaguni Monument in the Sea of Japan
Off the east coast of Yonaguni Island, Japan, lies a controversial underwater structure, known as the Yonaguni Monument. This structure was discovered in 1986 by diver Kihachiro Aratake. About 150 meters long and 50 meters wide, this formation resembles striking terraces.
Some theories state that the Yonaguni Monument is the work of humans from a lost ancient civilization. However, other scientists believe that these structures formed naturally due to tectonic activity and erosion. Until now, the origin of this monument is still a mystery.
2. The “Bloop” Sound from the Ocean
In 1997, NOAA (National Oceanic and Atmospheric Administration) recorded a mysterious sound called the “Bloop”. This sound has a low frequency and an incredibly large amplitude so that it can be heard from thousands of kilometers away.
It remains a captivating part of the Mystery of the Ocean, intriguing scientists and explorers as they try to uncover its origin and significance.
Initially, the sound was thought to be coming from an unknown giant sea creature. However, in 2011, NOAA concluded that the “Bloop” was coming from a glacier cracking in Antarctica.
However, not everyone is satisfied with this explanation, and the sound remains one of the most mysterious marine phenomena.
3. The Loss of Four Submarines in 1968
The year 1968 was a year full of mystery at sea when four submarines from different countries disappeared simultaneously. The four ships were the USS Scorpion (United States), K-129 (Soviet Union), Minerve (France), and INS Dakar (Israel).
The ships disappeared at different times and locations, but the exact cause remains a mystery. Theories range from technical accidents to sabotage during the Cold War. Of all these ships, only the Minerve has never been found.
4. Mysterious Structures in the Baltic Sea
In 2011, the Ocean X research team discovered a strange structure on the bottom of the Baltic Sea using sonar scanning. The circular structure was about 60 meters in diameter, resembling a “flying saucer” from outer space.
Some geologists believe that the structure is a remnant of the movement of glaciers during the Ice Age. However, members of the Ocean X team reported strange occurrences such as electrical equipment going dead when they approached the structure. To this day, the structure in the Baltic Sea remains one of the biggest mysteries.
5. Kraken: Giant Sea Monster
The Kraken legend comes from Norse and Scandinavian mythology, which describes a giant creature resembling an octopus or squid that can sink large ships. Although considered a myth, the discovery of a giant squid (Architeuthis dux) over 10 meters long proves that such a sea monster did exist.
However, there is no concrete evidence to suggest that the Kraken as in the legend was actually real, leaving questions about the origin of this story.
6. Mysterious Sound in the Ocean
In addition to the “Bloop”, other strange sounds such as “Julia” and “Upsweep” have also been recorded in the ocean. These sounds often occur at night, in the darkness of the ocean, and have no apparent origin.
Some scientists believe that these sounds are caused by natural phenomena such as volcanic or tectonic activity. However, some others suspect that the sound comes from an unidentified sea creature.
7. Atlantis: The Legendary Lost City
The legend of Atlantis, a lost city beneath the sea, has captivated researchers and archaeology enthusiasts for centuries. Several claims of Atlantis’ discovery have emerged from the Greek island of Delos, where ancient buildings, courtyards, and pottery have been found.
Although some archaeologists are skeptical of these claims, similar discoveries continue to fuel speculation about the existence of the legendary underwater city.
8. Sea Monsters in Stronsay
In 1808, the carcass of a strange creature washed up on the shore of Stronsay, Scotland. The carcass is about 11 meters long, with a shape that resembles a Plesiosaurus, an extinct marine reptile.
Some scientists speculate that the carcass is a decomposing shark, but the description and length of the creature make it difficult to explain. Until now, this phenomenon remains one of the unsolved mysteries of the sea.
9. Anomaly in the Baltic Sea
In addition to the circular structures, the Baltic Sea is also home to other unusual anomalies. In 2011, another shape discovered with sonar sparked speculation about a crashed spaceship, secret military technology, or a strange natural formation.
Scientists continue to study these formations, but there is no consensus on their origin or function.
10. Mysterious Sounds in the Deep Sea
The deep ocean is a mysterious place, with strange sounds often heard without a clear source. Some of the most famous sounds include “The Bloop”, “Upsweep”, and “Julia”, all of which have unique characteristics.
Although some sounds have been explained as the result of natural phenomena such as ice cracking or volcanic activity, many others remain unexplained, leading to speculation about the existence of creatures or phenomena unknown to humans.
The ocean is a world full of mysteries, from fascinating underwater structures to strange, confusing sounds.
Although many new discoveries have provided answers to some of these phenomena, most remain unsolved, reinforcing the ocean’s appeal as a key part of the World of Mystery and one of the final frontiers for human knowledge.
Ocean exploration continues, giving hope that one day we may uncover the secrets hidden in the vast blue depths. Until then, these mysteries will continue to captivate our imaginations and curiosity.
