Okay, so 10 wasn't enough to cover all the mysterious stuff calling out for explanation. So here are the next ten...
10. Stonehenge. Sacrificial site, astronomical calendar? Did the Druids build it or just move in because it was already there? And of course, exactly how did they move those stones?
9. Buddha Statues at Bamiyan, Afghanistan. Supposedly built by monks in the 6th century, hewn out of the sandstone cliffs. They survived Genghis Khan's wrath - only to be dynamited by the Taliban in 2001. Still, a lot of legends and mystery. Some say there's evidence that the monks only built their temples in the caves around the statues that were already there...
8. Who really got to America first? And who visited before Columbus? Far from decided, the issue won't go away as stubborn artifacts and lost settlements keep turning up all across the Americas and messing with what I learned in history class. Then there's the matter of maize (a uniquely new world crop) being found in Egyptian tombs...
7. The Olmecs. Precursers to the Maya. Great sculptors who left behind massive stone heads across Central America. Yet almost nothing is known about them.
6. The Antikythera Mechanism. Built around 150BC, recovered from a shipwreck in the Greek Isles in 1900, it seems to be a mechanical computer designed to calculate astronomical positions... A device with complexity that wasn't seen until the 15th century.
5. Shamballa. Ancient texts predating Tibetan Buddhism speak of a legendary city of peace and tranquility, full of spiritual wisdom. Is it myth or reality?
4. Angkor, Cambodia. The largest religious site in the world. A Hindu temple complex and 170 square mile area at one time home to over a million people and one of the greatest civilizations of the time; mysteriously abandoned in the late 12th century. Overrun by the jungle and not discovered again until 1860. Locals claimed it was built by the giants. What did them in? And what about some of the more interesting myths about the temples' construction?
3. Puma Punku / Tiahuanaco - Bolivia. The 'port' city of Tiahuanaco, is dated around 200AD - but there's tantalizing evidence that it's much older. Huge blocks, weighing 100-200 tons are scattered about like matchsticks (large distances form the nearest quarry), while others are connected by metal clamps as sections of immense partitions and docks. The nearest body of water is twelve miles away, yet the site contains millions of fossilized sea shells. Something - possibly a geologic upthrust - wreaked havoc on this city, tossed the immense blocks about and lifted this area away from the shores of some ancient sea. Tons of questions, but the biggest one is -when did this all happen, and was this city really built 15,000 years ago or more, as some believe?
2. Gobekli-Tepe, Turkey. A recent discovery, still being excavated. Dated to around 11,500 BC. Purposely buried (why?) in 8000 BC. A Stonehenge-like temple, built and complemented over several millennia has been unearthed - and yet only about 5% of the expected structures have been revealed. What other secrets are there? Some are calling it the original Garden of Eden, but whatever it was, nothing like that, on this scale and sophistication, was thought possible for neolithic hunter-gatherers...
1. Mohenjo-Daro, Pakistan. Translated as "The Mound of the Dead", Mohenjo-Daro was one of the world's oldest cities, believed to have been built around 2600 BC. Along with its sister city, Harrapan, they were centers of the Indus Valley civilization. At some point both vanished suddenly from history until rediscovered in the 1920's. What's truly mind-boggling is that these sites have a high degree of radioactivity:
"...in an epicentre 150 feet wide, everything was crystallised, fused or melted; 180 feet from the center the bricks are melted on one side, indicating a blast. Excavations down to the street level revealed 44 scattered skeletons, as if doom had come so suddenly they could not get to their houses. All the skeletons were flattened to the ground. A father, mother and child were found flattened in the street, face down and still holding hands. It has been claimed that the skeletons, after thousands of years, are still among the most radioactive that have ever been found, on a par with those of Hiroshima and Nagasaki."
There are theories that the destruction of these cities are actually described in the Vedic epic, The Mahabarata, which details warfare between two races and the destruction of cities with 'lightning bolt' weapons, missiles that caused great devastation and left the survivors suffering with symptoms that seem like radiation sicknes...