Carvings chiseled into a large stone pillar in Turkey nearly 13,000 years ago may be the world's oldest sun-and-moon calendar, a new study suggests. And the calendar may have been carved to mark a catastrophic comet strike.
Archaeologists discovered the markings at Göbekli Tepe, an archaeological site in southern Turkey that's known for its abundance of temples with elaborately etched drawings, according to the study, which was published July 24 in the journal Time and Mind.
