Gangtok, March 25 -- Throughout history, archaeologists have unearthed objects that defy explanation, hinting at advanced knowledge, lost civilizations, or alternative versions of the past. Here are ten of the most puzzling artifacts ever discovered-and the intriguing theories behind them.

1. The Antikythera Mechanism (c. 100 BCE, Greece) - The World's First Mechanical Computer

Recovered from an ancient shipwreck off the coast of Antikythera, this bronze device is considered one of the most advanced technological artifacts of the ancient world. With a complex system of gears, it could predict eclipses and planetary movements.

Its level of precision shocked historians, suggesting that ancient Greek science was far more sophisticated tha...