8 Amazing Structures With Mysterious Origins

Large carved stone heads on Easter Island
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Many people visit historical places because they want to see firsthand where an important event took place or where an often-told narrative played out. The allure of these legendary sightseeing spots has everything to do with the historical facts that surround them.

But even in the modern age, the origins of many sites, both modern and ancient, remain a mystery. Experts and enthusiasts have provided theories about these strange places, but there's nothing concrete to satisfy the innate human desire to know the answer to the question: "Why is this here?"

These odd sites can be attractive because of that lack of information. Some tourists come to soak in the atmosphere and relish the sense of mystery that surrounds these places, while others want to concoct their own theories about the site's origin or to create their own fantastical narrative.

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Nan Madol

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Located in the South Pacific nation of Micronesia, the imposing stone structures of Nan Madol sit on top of a coral reef in a lagoon adjacent to the island of Pohnpei. A network of natural "canals" connect the different islets of this ancient complex. Carbon dating put the earliest settlements in the area at about A.D. 1200, though some archeological finds suggest that people were living on Pohnpei over 2,000 years ago.

We know little about the curious monolithic structures on the islets of Nan Madol. The large stone blocks that make up the structures are too heavy to have been lifted into place without some sort of mechanical aid. Many theories and myths have exist about the origin of these buildings, ranging from local legends involving sorcerers and black magic to fantasies that hypothesize about a "lost race" that came from a now-disappeared continent. There are also more believable (but unproven) theories that suggest that Nan Madol was some sort of royal complex meant to keep the island's elites separate from the common people.

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Skara Brae

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Located on Scotland's rugged Orkney Islands, the round mound-like buildings of Skara Brae are in remarkably good condition considering they are thought to be much older than the Great Pyramid of Egypt. Most estimates put these structures at 5,000 years of age. The settlement has been called the "Scottish Pompeii," not because a volcano destroyed it, but because it remains in almost pristine condition despite being abandoned thousands of years ago. Dry sand blown in from Orkney's coastal dunes preserved the buildings.

The eight dwellings of Skara Brae and the passageways that connect them are now a popular attraction for tourists, many of whom come via cruise ship. These dwellings have brought scientists a great deal of insight about life in Scotland in Neolithic times, but the history of this site remains mysterious. Human remains, carvings and a bull's head were found in a building that was isolated from the rest of the complex, inspiring theories about ancient religious rituals. Also, it's uncertain whether it was the encroaching dunes or some catastrophic event that caused residents to abandon the village more than 4,000 years ago.

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Newport Tower

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One of the more mysterious structures in the United States, the Newport Tower is a circular stone building in Newport, Rhode Island. The most believable (but least interesting) theory is that the tower was originally the base of a windmill built in the 1600s or 1700s by some of America's first European settlers. However, some people hypothesize that it's several hundred years older than commonly thought and provides evidence that someone other than Columbus made the first landing in the New World.

Carbon dating of the foundation and excavations of the surrounding areas seem to support the windmill hypothesis. However, there's also speculation that the tower was some sort of observatory because its windows align with various stars and moon positions. There are also windows that align with the sun's position during the summer solstice. These odd features have led to theories about Vikings, Chinese sailors and even that the Knight Templars were responsible for the construction of the tower.

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Easter Island moai

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The most famous of the world's mysterious statues are found on Easter Island (often referred to by its indigenous name, Rapa Nui). The huge-headed statues, known as moai, were carved and erected by the island's inhabitants between the 13th and 16th centuries. Little is known about how these massive statues were carved and then moved to various points around the island without the aid of modern equipment. The heaviest of the moai weighs about 82 tons.

Because the statues resemble those found in other parts of Polynesia, it is believed that they represented the faces of the islanders' clan ancestors. Rapa Nui's own story adds to the sense of mystery created by the massive-headed icons. The island is completely deforested and early European sailors who landed there found a civilization in disarray and the few natives left sick or starving. These early encounters showed little evidence of a society that was advanced enough to carve and transport the moai.

However, a team of scientists believes the islanders were strategic when placing the maoi around the island. The scientists analyzed the locations of the maoi to determine if they were located near "resources thought to be the focus of competition in precontact times." They looked for evidence of rock mulch agricultural gardens, marine resources and especially freshwater sources since the island didn't have a permanent freshwater source above ground. What they discovered was the maoi were located near underground aquifers and areas where fresh groundwater ran off into the ocean. The islanders were known to drink brackish water, and the maoi would explain why they were so important in helping the people know how to find the most drinkable water. It would also explain why so many perished by the time European settlers arrived since the water was likely contaminated.

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Olmec colossal heads

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Carved from basalt boulders, these large, head-shaped statues are much older than the more-famous statues on Rapa Nui. Found at various sites in the Olmec heartland along the Caribbean coastline in both Mexico and Guatemala, many of the heads are remarkably well-preserved and quite lifelike. They bear distinct features still seen in the Central American descendants of the Olmec.

Each head is carved out of a single boulder, with the smallest example weighing 6 tons and the largest (an uncompleted head) topping 50 tons. The best-kept examples are in the Mexican state of Veracruz. The methods of transporting these boulders remain unclear, and heads found in different areas have slightly different characteristics, leading to the theory that they were modeled on actual people. The Olmec were very skilled artists, and other works were found throughout the Veracruz area. The Olmec civilization went into steep decline and virtually disappeared over 2,000 years ago, with the carvings among the only clues to the story of a once-thriving civilization.

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Stonehenge

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Along with the moai of Rapa Nui, Wiltshire, England's Stonehenge is one of the most famous mysterious structures in the world. Archeologists believe the ring of stone pillars with massive capstones perched on top was erected between 4,000 to 5,000 years ago. There are more theories and legends surrounding this place than at any other prehistoric site on Earth. There are no concrete facts about the purpose of Stonehenge, but many people think it's somehow religious, and there's evidence that it was used as a burial ground at some point (human remains were excavated from a ditch near the structure).

The most widely accepted theory is that it was a multi-purpose religious site for burial and worship of ancestors or deities. The south central part of England, where Stonehenge is located, was densely populated during the Neolithic Age, and numerous burial mounds and artifacts have been found there. This has allowed scientists to at least give Stonehenge some historical context if not to find answers about its exact purpose or the method of construction used to create it. The site also has significance to modern practitioners of the Druid faith.

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Georgia Guidestones

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Not all mysterious sites have ancient origins. One of the strangest structures on our list has only been around for just over three decades. Located in northeast Georgia's rural Elbert County, the six Georgia Guidestones (five upright and one Stonehenge-esque capstone on top) were erected by contractors under the direction and funding of a person or people who have remained anonymous to this day.

Ten items are listed in eight different languages on the face of the stones (in English, Spanish, Swahili, Hindi, Hebrew, Arabic, Chinese and Russian). This cryptic (though not necessarily religious) list has been referred to as some sort of version of the Ten Commandments for a post-apocalyptic time. On a small tablet near the main structure, there are statistics about the size and astronomical alignment of the stones and also the inscription, "Let these be guidestones to an Age of Reason." Since the people behind this project remain anonymous, the stones have inspired various conspiracy theories (some of them quite wild and colorful). Some people have pointed out that the "commandments" are in line with the teachings of various secret societies around the world.

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Pumapunku

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Pumapunku (often written as two words: "Puma Punku") is part of the larger Tiwanaku archeology sites in the Andes of Bolivia. Sitting a short distance from the famed Lake Titicaca, the stones of Pumapunku are at the center of one of South America's most intriguing historic mysteries. The stones are laid out with accuracy, and the geometrical carvings are extremely precise. The straightness of the cutting is like that achieved in modern times with the use of lasers and computerized equipment.

The quality of the artistry has led to various theories, with some people attributing the stones to aliens and others to some super-advanced society that vanished from the face of the earth after some sort of catastrophic event. More reasonable Pumapunku theories include the idea that the stones were not natural, but made using some sort of concrete and molds. Others suggest that the ancient craftsmen were just extremely skilled and used methods that historians and archeologists haven't discovered or thought of yet.