They’re evidence of extraterrestrial visitation, time travelers or lost civilizations like Atlantis – or perhaps they’re here to show us that some ancient peoples were far more advanced than we think. It’s hard not to get caught up in the mystery and intrigue of these puzzling and often bizarre ancient objects, most of which simply can’t be explained by modern science.

Antikythera Mechanism

The world’s oldest computer predates Bill Gates only by about 2,000 years. In fact, the absolutely mind-boggling Antikythera Mechanism – a corroded clocklike object found among the ruins of a sunken ship – may prove that advanced scientific technology existed far earlier than we ever thought possible. Scientists have since discovered that this mysterious Greek invention predicted solar eclipses, organized the calendar in four-year cycles, and may well be linked to renowned astrologer and engineer Archimedes. Though no other such mechanisms have ever been found, experts believe that many more made around the same time in 100 B.C.E. once existed.

Baghdad Battery

What need would ancient people have for batteries when electronics did not yet exist? Found outside Baghdad, Iraq in 1936, the Baghdad Battery is a small clay jar containing an iron rod suspended in a copper cylinder which is soldered shut and sealed with asphalt. Replicas that have been made since then can produce small mounts of electricity, proving the battery’s capabilities, but the question of what the battery was used for many never be answered.

The Baigong Pipes
“Alien toilet found in China”. This is just one of many absurd headlines seen on the internet concerning the undoubtedly bizarre Baigong Pipes, rusty red iron pipes that lead into a pyramid atop Mount Baigong from a nearby salt water lake. What’s so strange about the pipes? Well, for one thing, they’re in an area that is completely inhospitable to man – no civilization is ever known to have lived there. They’re uniform in size and seem to have been created in an intentional pattern. No clear explanation exists for the presence of these pipes, and scientists don’t seem to agree on whether they could be natural occurrences.

The Coso Artifact

When a spark plug was found encased inside a 500,000-year-old lump of hard rock, self-professed paranormal investigators decided there were three possibilities for how it got there: A, it was created by an extremely advanced ancient civilization (maybe Atlantis?), B, aliens visited the earth during the time of dinosaurs or C, time travelers from the future left clues in the distant past. All three explanations are highly unlikely to say the least, but scientists haven’t been able to come up with a better explanation – probably due to the fact that the Coso Artifact has mysteriously disappeared and is thus unavailable for analysis.

The Maine Penny
When a genuine Norse coin dating to the early 11th century was found among Native American ruins in Maine in 1957, it seemed to offer an intriguing piece of evidence that Vikings did indeed travel further south than Newfoundland long before the time of Christopher Columbus. And it could be so – but experts have their doubts. The fact that the ‘Maine Penny‘ was the only Norse artifact found at the site seems to indicate that it came to the site through native trade channels from Viking sources in Labrador and Newfoundland.

Phaistos Disc
There’s very little that we actually know for sure about the Phaistos Disc. It’s made of clay – check. It dates back to the second millenium B.C.E. – maybe. But its origin, meaning and purpose remain shrouded in mystery. Discovered in Crete, the disc is features i241 impressions of 45 distinct symbols, some of which are easily identifiable as people, tools, plants and animals. But because nothing else like it from the same time period has ever been found, archaelogists haven’t been able to provide a meaningful analysis of its content.

The Roman Dodecahedra

These fist-sized bronze Roman artifacts found in France, Switzerland and Germany pose a fascinating problem for archaeologists: they just don’t have a clear purpose, but many are covered in symbols, some undecipherable and others relating to the Zodiac. But for all the speculation on their use, including that they may have been surveying instruments, some experts believe the Roman dodecahedra were merely decorative candlesticks.

Shroud of Turin

A linen cloth bearing the barely-visible image of a man with apparent crucifixion wounds became the center of both devotion and controversy when it was first discovered in the Middle Ages. Could this be the burial shroud of Jesus Christ? Radio carbon dating puts the origin of the shroud between 1260 C.E. and 1390 C.E., consistent with the theory that it was a forgery. But the results have been disputed and since then, a wide range of modern tests have been unable to explain the markings on the cloth.

The Giant Stone Spheres of Costa Rica
They appear to be flawlessly round, ranging in size from just a few centimeters to over 6.6 feet in diameter, and are found all over the Diquis Delta and Isla de Cano in Costa Rica. Weighing up to 16 tons, it’s hard to imagine how humans could have moved these gigantic sculptures hewn from hard granodiorite – considering that the nearest quarry for that material is over 50 miles away from where the sculptures were found. Over three hundred of them are scattered across Costa Rica, but we’ll never know why – the people who made them back in 1,000 C.E. are long gone and had no written records.

Voynich Manuscript

Is the Voynich Manuscript evidence of a forgotten civilization, or merely an elaborate hoax? This handwritten book full of text that the world’s top cryptographers and codebreakers have never been able to decipher dates to the 15th century and was discovered in 1912 by book dealer Wilfrid M. Voynich. If it is a hoax, it’s incredibly convincing, given how fluidly the text was written and the fact that statistical analysis has revealed patterns similar to those found in natural languages.