[osreb]

The world is filled with ancient monuments built by master craftsmen in order to honor everything from kings and presidents to religious figures. And although most of these landmarks have been carefully studied and researched by scientists and historians, some are simply so old, incomplete, or obscure that we still dont know very much about why they were built or what purpose they served. The following are 10 world landmarks that, whether by intention or simply due to the passage of time, continue to baffle the people who study them.

10. The Cahokia Mounds
Cahokia is the name given to an Indian settlement that exists outside of Collinsville , Illinois . Archeologists estimate that the city was founded sometime around 650 AD, and its complex network of burial grounds and sophisticated landscaping prove that it was once a thriving community. It has been estimated that at its peak the city was home to as many as 40,000 people, which would have made it the most populous settlement in America prior to the arrival of the Europeans. The most notable aspect of Cahokia today are the 80 mounds of earth, some as high as 100 feet, which dot the 2,200-acre site. These helped create a network of plazas throughout the city, and it is believed that important buildings, like the home of the settlements chief, were built on top of them. The site also features a series of wooden posts that archeologists have dubbed woodhenge. The posts are said to mark the solstices and equinoxes, and supposedly figured prominently in the communitys astronomical mythology.

The Mystery
Although scientists are constantly discovering new information about the Cohokia community, the biggest mystery that remains is which modern Indian tribe is descended from the residents of the ancient city, as well as just what it was that caused them to abandon their settlement.