Five Unsolved Mysteries

1. The mighty Incan Empire of South America.

The mighty Incan Empire of South America flourished between 1200 and 1535 AD. They developed drainage systems and canals to expand their crops, and built stone cities atop steep mountains — such as Machu Picchu (above) — without ever inventing the wheel. Despite their vast achievements, the Incan Empire with its 40,000 manned army was no match for 180 Spanish conquistadors armed with advanced weapons and smallpox.

2.Ancient Pyramids in Giza , Egypt

Khafre (l.) and Khufu (r.) are two of the three ancient Pyramids in Giza , Egypt . Khufu is the biggest, consisting of more than 2 million stones with some weighing 9 tons. The Pyramids, built as elaborate tombs for divine kings, date back to 2,550 BC. Modern Egyptologists believe that the Pyramids are made from stones dragged from quarries and, despite ancient Greek testimony, were built predominantly by skilled craftsmen rather than slave labor.

3. The Mayan Temple

According to the Mesoamerican Long Count Calendar, made famous by the ancient Mayan people, December 2012 marks the ending of the current baktun cycle. This little bit of information has many archeologists spooked. Some believe the Mayans were warning of a coming apocalypse, while others insist it’s simply a mathematical misconception.

4. The Legend of El Dorado.

The Legend of El Dorado originates from the Muisca, who lived in the modern country of Colombia from 1000 to 1538 AD. In a ritual ceremony for their goddess, the tribal chief would cover himself in gold dust and jump into a lake as an offering. This spawned the legend of a lost golden city, which led Spanish conquistadors on a wild goose chase to nowhere.

5. Easter Island

Easter Island, also known as Rapa Nui, is remotely located 2,000 miles off the coast of Tahiti . The original settlers of the island were Polynesians who migrated to the far-off land between 400 and 600 BC. They built many shrines and statues, called moai, from stones quarried throughout the island including a volcano site. Researchers still question exactly how the large stones were moved.