5 Mysterious ruins that predate known civilization?
Artifacts and ruins discovered all over the world have made many scientists question whether the currently accepted understanding of prehistoric culture is correct.
Here's a look at some disputed sites, thought by some to hold evidence of prehistoric civilizations far more advanced than scientists thought possible. Some of these structures have been submerged as sea levels have risen over the course of thousands of years.
1. Bosnian Pyramid oldest in world: 25,000 years old:
Two Italian archaeologists, Dr. Ricarrdo Brett and Niccolo Bisconti, found a piece of organic material on the pyramid last year. They were able to carbondate the material, and with it, the pyramid itself. This carbon dating places the pyramid 20,000 years before the Sumerian and Babylonian civilizations, believed to be some of the earliest in the world.
When the Bosnian Pyramid was first discovered in 2005, researchers could only measure the age of the topsoil covering the pyramid, which is about 12,000 years old.
Dr. Semir Osmanagich, a researcher woorking on the Bosnian Pyramid told NTD Television last year: "The organic materials found on the Sun Pyramid and biological analysis are telling us that the pyramids are older than 12,500 years - the oldest on the planet."
Since the pyramid was covered with soil and vegetation, people thought it was just a hill until the stone structure within was discovered. It was known as Visoko hill.
While many local scientists back Osmanagich, there are skeptics. Boston University geologists Robert Scoch, who spent 10 days on site, told Smithsonian magazine in 2009 that the pyramid is a natural formation. Paul Heinrich, an archaeological geologists at Louisiana State University agreed. Heinrich told Smithsonian: "The landforn [Osmanagich] is calling a pyramid is actually quite common.......They're called 'flatirons' in the United States and you see a lot of them out West."
Enver Buza, a surveyor from Sarajevo's Geodetic Institute has stated in paper that the pyramid is "oriented to the north with perfect precision," reported Smithsonian. Some say the case of Bosnia's pyramids has been for political gains.
2. Gobekli Tepe, Turkey: 11,000 years old
Gobekli Tepe in Turkey is made up of massive stone megaliths that predate Stonehenge by about 6,000 years. It's believed by archaeologist Klaus Schmidt that this is the oldest human place of worship - at least 11,000 years old - built at a time when scientists say people hadn't even developed agriculture.
Stanford University archaeologist Ian Hodder told Smithsonian magazine the prehistoric structures in Gobekli Tepe could change how science views prehistoric culture.
"The dating is clear, there is n question about it," Schmidt said in a Red Ice Creations radio interview. With a combination of carbon dating and using the age of surrounding structures, Schmidt is confident Gobekli Tepe is at least 11,000 years old.
"The astonishing fact is that we did not expect for a hunter gatherer society to be able to manage such an operation, to transport a megalith," he said.
With ground-penetrating radar scans, Schmidt and his team have determined that at least 16 other rings of megaliths are still underground across 22 acres, according to the 2008 Smithsonian article. Even in 50 years, he said, much digging will be left.
Engraved on the megaliths are images of vultures, waterfowl, spiders, and many other creatures.
3. Yonaguni Monument, Japan's Atlantis: 8,000 years old
Believed by some to be built more than 8,000 years ago, before the last Ice Age, a large structure off the coast of Japan's Yonaguni island has been cited as evidence an advanced culture thrived thousands of years earlier than current text books say.
British journalist Graham Hancock and Professor Masaaki Kimura of the Ryukyus in Okinawa studied the structure after it was discovered by a diver in 1987.
Kimura agrees with Hancock that humans either formed the structure or modified a natural formation.
"It looks like a monument," Hancock told the BBC. "It has very curious features. It has a series of steps and terraces cut into its side. It's oriented to the cardinal directions. It faces due south, it has a deep east-west feature running along in front of it. It bears all the hallmark of a designed, ceremonial, ritual or religious monument."
Schoch, the same skeptic in the Bosnian pyramid case, disagrees. He told the BBC that "portions of it look like they're man-made," but the way the rock splits naturally could make the formation.
"I think it should be considered a primarily natural structure until more evidence is found to the contrary. However, by no means do I feel that this is an absolutely closed case," he wrote in a 1999 paper.
4. Gulf of Khambhat, Israel: 9,500 years old
At the bottom of Israel's lake Kinneret, also known as the Sea of Galilee, is a massive, enigmatic structure that could be more than 9,500 years old.
It was discovered by the National Institute of Ocean Technology in 2000 in the Gulf of Khambhat. The circular structure made of boulders and rocks spans about 9 kilometers (5 miles). It has only been explored via sonar scanning and dredging. At least one artifact brought up by dredging has been dated to 7,500 BC, according to Princeton University.
The Princeton website explains why some archaeologists refuse to accept the date in relation to the structure itself: "One major complaint is that artifacts at the site were recovered by dredging, instead of being recovered during a controlled archaeological excavation. This leads archaeologist to claim that these artifacts cannot be definitively tied to the site."
Dani Nadel, an archaeologist at the University of Hafia who is working with a team to study the discovery, told Fox News in May: "It's very enigmatic, it's very interesting, but the bottom line is we don't know when it's from, we don't its function," he said. "We only know it is there, it is huge, and it is unusual."
5. Bimini Road: 12,000 years old
Two camps of scientists have faced off on the issue of the underwater structure known as Bimini Road off thee coast of the Bahamas since it was first discovered in 1968.
One camp says it is a 12,000-19,000 years old man made structure - flouting the conventional understanding that advanced civilizations only emerged some 5,000 years ago.
The other camp says it is a natural formation.
Explorer Dr. Greg Little has performed multiple documented dives at the site with archaeologist William Donato.
Donato explained in an email to the Epoch Times that the line of stones form a wall, known as a breakwater, built to protect a prehistoric settlement from waves. During their dives and Little found the structure to be multi-tiered and to include prop stones they say must have been placed there by humans.
Little wrote in a 2005 paper that a neutron activation analysis compared nearby shore stones to the Bimini Wall stones and showed the Bimini stones had fewer trace elements, suggesting they were formed elsewhere and transported to that location.
