Sometimes, these leftovers were exceptionally beautiful works of art, but it was considered unscientific speculation to attempt to reconstruct the beliefs behind their creation and use.

Now, however, it's generally recognized that ceremonial objects and structures can provide key insights into many facets of ancient cultures. In fact, some archaeologists think ceremony was the key to the origins of civilization.

In the Jan. 18 issue of the journal Science, German archaeologist Klaus Schmidt is interviewed about his work at the 11,000-year-old site of Gobekli Tepe ("navel hill") in Turkey.

According to Andrew Curry, the author of the Science article, Gobekli Tepe is situated on the most prominent hilltop for miles around. It consists of at least 20 underground rooms that contain a number of T-shaped stone pillars that are 8 feet tall and weigh about 7 tons. The pillars are engraved with images of animals, including leopards, snakes and spiders.

This is not a place where people lived. It's as far away from water as you can get in this region. Instead, it's a place of ceremony. And, according to Schmidt, it's "the first manmade holy place."

To find such a large ceremonial center at such an early time period suggests that it was the need for communal rituals that first brought people together. Agriculture, pottery, domesticated animals and cities all came later.

Perhaps it was religion and not technology that fomented the Neolithic Revolution and led to the rise of civilization.

Archaeologist Steven Mithen, in his book After the Ice, writes that it was at Gobekli Tepe "that the history of the world had turned."