The difficulties scientists face in uncovering the mysteries of the sea lie in their limited technology and knowledge. The high cost of research also poses a challenge in revealing these sea mysteries. Compiled from various sources, here are 8 maritime events that remain a mystery to this day.

"Speculation regarding the structure involves theories of spacecraft, secret war technology, and Nazi bunkers. However, the crew that discovered the structure refutes these theories because the electrical equipment failed as they approached the structure. Geologists concluded that it was the Baltic Sea Anomaly, which is a glacial deposit that moved during the Ice Age. Nevertheless, to this day, the strange structure remains a mystery without a satisfactory explanation."

The four submarines went missing over a period of five months consecutively. Although more than half a century has passed, the cause and fate of the crews of the four vessels remain unknown.

"With a length of 50 meters and a width of 20 meters, the monument found at the southern tip of the Ryukyu Islands still invites debate as to whether it is the result of modifications to natural rock or human construction."

"This event puzzled scientists for years. However, 14 years later, scientist Robert Dziak from NOAA explained that the bloop was the sound of an icequake caused by the breaking of the ice layer from the Antarctic glacier. Nevertheless, this explanation was not fully accepted by some other scientists who are still trying to find out what caused 'the bloop'."

"This ship went missing mysteriously, but was found floating with the engine still running. Due to its mystery, Kaz II earned the nickname 'Ghost Ship of Australia'. Theories suggest one of the sailors fell into the sea, and when the other two tried to rescue him, they also disappeared."

This city was discovered with an underwater robot equipped with sonar light at a depth of 700 meters. From the exploration of the underwater robot, many building ruins, statues, and other signs of human life were revealed.

"This trench can even submerge Mount Everest, which is the highest peak on Earth (8.8 thousand meters). There is currently no technology that can withstand the immense water pressure within it. Therefore, there has not yet been an expedition that can fully explore the depths of the Mariana Trench."

This story was first told by the Greek philosopher Plato about 2,300 years ago, describing a great city that sank beneath the Atlantic Ocean. Since then, various theories have emerged to explain the mystery of Atlantis. Some mention the disappearance of Atlantis related to the Bermuda Triangle, meteor strikes, natural disasters, or even consider Atlantis to be ancient Antarctica. Others argue that Atlantis is actually just a myth and never truly existed.