NOT 12,000 OLD!!! You can not "carbon date" a stone structure. The dated parts were remains of organic materials (fire pits, animal bone remains, etc.) found in the area. All we know is that the structures were build on a site with human activity going back around 12,000 years. Smithsonian is also using seriously flawed methodology to make the age guestimate based on artifacts found nearby "closely resembling others from nearby sites previously carbon-dated to about 9000 B.C.". PLEASE, there is not such thing as carbon dating of stone structures!