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The Grooved Spheres
Over the last few decades, miners in South Africa have been digging up mysterious metal spheres. Origin unknown, these spheres measure approximately an inch or so in diameter, and some are etched with three parallel grooves running around the equator. Two types of spheres have been found: one is composed of a solid bluish metal with flecks of white; the other is hollowed out and filled with a spongy white substance. The kicker is that the rock in which they where found is Precambrian - and dated to 2.8 billion years old! Who made them and for what purpose is unknown.
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The Dropa Stones
In 1938, an archeological expedition led by Dr. Chi Pu Tei into the Baian-Kara-Ula mountains of China made an astonishing discovery in some caves that had apparently been occupied by some ancient culture. Buried in the dust of ages on the cave floor were hundreds of stone disks. Measuring about nine inches in diameter, each had a circle cut into the center and was etched with a spiral groove, making it look for all the world like some ancient phonograph record some 10,000 to 12,000 years old. The spiral groove, it turns out, is actually composed of tiny hieroglyphics that tell the incredible story of spaceships from some distant world that crash-landed in the mountains. The ships were piloted by people who called themselves the Dropa, and the remains of whose descendents, possibly, were found in the cave.
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The Ica Stones
Beginning in the 1930s, the father of Dr. Javier Cabrera, Cultural Anthropologist for Ica, Peru, discovered many hundreds of ceremonial burial stones in the tombs of the ancient Incas. Dr. Cabrera, carrying on his father's work, has collected more than 1,100 of these andesite stones, which are estimated to be between 500 and 1,500 years old and have become known collectively as the Ica Stones. The stones bear etchings, many of which are sexually graphic (which was common to the culture), some picture idols and others depict such practices as open-heart surgery and brain transplants. The most astonishing etchings, however, clearly represent dinosaurs - brontosaurs, triceratops (see photo), stegosaurus and pterosaurs. While skeptics consider the Ica Stones a hoax, their authenticity has neither been proved or disproved.
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The Antikythera Mechanism
A perplexing artifact was recovered by sponge-divers from a shipwreck in 1900 off the coast of Antikythera, a small island that lies northwest of Crete. The divers brought up from the wreck a great many marble and and bronze statues that had apparently been the ship's cargo. Among the findings was a hunk of corroded bronze that contained some kind of mechanism composed of many gears and wheels. Writing on the case indicated that it was made in 80 B.C., and many experts at first thought it was an astrolabe, an astronomer's tool. An x-ray of the mechanism, however, revealed it to be far more complex, containing a sophisticated system of differential gears. Gearing of this complexity was not known to exist until 1575! It is still unknown who constructed this amazing instrument 2,000 years ago or how the technology was lost.
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Here's Mitchell Hedges' famous crystal skull. Close inspection of the piece shows that there are no scratches or marks to indicate it had been carved with metal instruments, it is also nearly perfectly anatomically correct. According to a researcher, "The damned thing simply shouldn't be."
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High in the mountains of Tibet, 12,000 feet above sea level, a small spirit house stands alone on a wind-swept ledge. Inside, is a corpse, but a corpse like no other. Believed to be centuries old, it has never decayed.
Link 1
Link 2
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These are "pyramids" found off the coast of Japan... near okinawa.
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Many of those artifacts and the mystery surrounding out of place objects is discussed in a book called "Time Travel for Beginners".Found this article about a early map with strange characteristics.
http://www.world-mysteries.com/sar_1.htm