The structures consist of enormous stone blocks, some of which are geometric and stacked similarly to other pyramids in the Americas. To this day, the site remains a mystery, with some suggesting it could be a lost civilization, whereas others argue it’s the remains of the fabled Atlantis.

The team was headed by marine engineer Pauline Zalitzki and her husband Paul Weinzweigl, owners of ADC. Their company was working alongside four other firms on behalf of Fidel Castro’s Cuban government to explore the treasure-laden shipwrecks, many of which date back to the Spanish colonial era.

The team of researchers suggests that humans likely built the structures on dry land. Over time, rising sea levels swallowed the structures, completely submerging them under the waves.

Zalitzki returned to the site the following year to conduct further investigations alongside her husband and expert geologist Manuel Iturralde, who was a senior researcher at Cuba’s Natural History Museum, per Ancient Origins.

The largest of the blocks measured 8 feet by 10 feet and appeared to have been carefully placed atop one another. At the time, Zalitzki suggested the images could be evidence of an ancient submerged city; however, she claimed more evidence was necessary.

According to Iturralde, it would have taken as much as 50,000 years for such a structure to sink to this depth. He added, “50,000 years ago, there wasn’t the architectural capacity in any of the cultures we know of to build complex buildings.”

According to the researcher, it may have once been an extensive urban settlement. He added, “It’s a really wonderful structure which really looks like it could have been a large urban center. However, it would be totally irresponsible to say what it was before we have evidence.”

Iturralde later suggested the volcanic rocks, which make up the bulk of the site, were once above water at a distant part in the past. However, he was completely sold on the idea that it was the product of an ancient civilization, stating, “Nature is much richer than we think.”

Zelitsky said the Atlantis story is a myth. “What we have found is more likely remnants of a local culture,” once located on a 100-mile “land bridge” that connected Mexico’s Yucatan Peninsula to Cuba.

It’s quite possible the sunken settlement may have once been the home to one of these groups before some natural calamity sent it to the bottom of the ocean. However, not everyone agrees with their theory, which suggests the formation is anything more than natural rocks.

According to the researcher, this supposed settlement could not have been the capital city of Atlantis, as it hasn’t been above sea level since well before the ice age.

He continued, “However if we take Plato at his word—as we must if we assume Atlantis to have been a historical place—the violence of its sinking makes it improbable that an entire city could have survived plunging more than 600 m into an abyss.”

Fitzpatrick-Matthews notes that the sea levels dropped by only 328 feet during the Pleistocene era, which spanned from about 2.5 million to 11,700 years ago. The stones would not have been above sea level unless the land beneath them sank.

According to his research, which is based on the maximum speed of the planet’s tectonic plate movement, it would have taken more than 50,000 years for the stones to have sunk as deep as they have.

“It would be cool if Zelitsky and Weinzweig were right, but it would be real advanced for anything we would see in the New World for that time frame,” Fought said. “The structures are out of time and out of place.”

An earthquake or volcanic activity may cause a cataclysmic event that sent the ancient city underwater. It’s a theory we have heard before from the famed Greek philosopher, Plato.

However, if the stones were merely the product of nature, it should have been fairly easy to explain what natural process led to their creation. As things stand, the story went cold after experts dismissed Zelitsky’s theory.

John Echave, a senior editor at National Geographic, stated that a team of highly skilled divers will need to study the stone features to find out if these rocks are naturally occurring. “They are interesting anomalies, but that’s as much as anyone can say right now,” Echave added.

To the experts, the stones have been organized in a way that is like urban development with many granite slabs stacked upon each other to form a pyramid-like structure.

Zelitsky cautioned that it is too early to conclude the stone structures or their purpose long before sinking into the ocean. However, she is excited about the possibility that the discovery could be significant to human history.

The Cuban government called off the other expeditions due to red tape. A blockade around the site and the rejection of permit applications from research teams have prevented further exploration.

Weinzweig asserts that the discovery of significant archaeology in the little-explored world’s oceans will greatly expand our understanding of human civilization’s enormous antiquity.

Scientists believe that the pyramid-shaped structure, an arch, staircases, and other shapes marked with ancient script, which submerged nearly 10,000 years ago, were man-made. However, others argue that these structures are naturally occurring like the symmetrical basalt columns in Iceland or on the Gaint’s Causeway in Northern Ireland.

Scuba divers can access Thonis-Heracleion, while the Underwater Archaeological Museum of Alexandria continues to uncover and study Alexandria’s ruins.