Diver visits Japan's ancient underwater 'pyramid' and says what he found was 'not natural'

A diver who visited Japan's ancient underwater 'pyramid' said that what he found at the site 'was not natural'.

Below the surface off the coast of Japan's Ryukyu Islands lies a number of 'pyramids' that were discovered by a local diver back in 1987.

Kenzo Watanabe visited the site (BBC Global/YouTube)

The structures were unveiled when Kihachiro Aratake was diving off the coast of Yonaguni Island in Okinawa.

In a completely coincidental discovery, he found a strange, pyramid structure on the ocean floor.

"I was very emotional when I found it," he told BBC Global.

"I realised that this would become a treasure of Yonaguni Island. I kept it a secret, I didn't tell anyone on my staff."

Also known as the Yonaguni Monument, one of the formations has been nicknamed the 'Atlantis' due to it's size and structure.

The monument is 50m long and 20m wide, featuring spiralling steps and flat surfaces.

For decades, the structures have mystified locals, with some believing they could be the remains of a previous civilisation.

But the number one question that geologists want to know is whether the monument was man-made or if it's simply a natural formation.

Speaking about seeing the structure during a dive, Kenzo Watanabe told the BBC that what he witnessed was 'not natural'.

"What first triggered me to go to Yonaguni is that if it was appointed as an archeological site, it was rumoured that we wouldn't be able to dive there anymore," he said.

"So I decided to go while I still could.

"I got together with a group of diving instructors that I'm close with and we all took vacation time to go.

"After seeing it, there's no way I think it's not man-made.

"Especially with all the flat surfaces. It was really overwhelming, with so many different surfaces and symmetrical shapes.

"I think it's definitely not natural. I really wondered how it was made.

"It made me think about the kind of tools people may have used back then. It's so mysterious."

The formation features steps and flat surfaces (Getty Stock Photo)

Despite many believing the structures to be created by humans, it's widely accepted that the formations are actually natural.

Scientists think that the monument is thousands of years old, therefore they have questioned whether humans would have been able to make such impressive formations so long ago.

Instead, many believe the pyramids have been shaped over the course of many years, by underwater currents, especially considering the structures are located within an earthquake zone.