Story highlights Investigation of Belize's "Blue Hole" indicates drought did in Mayan civilization

Mayan civilization peaked in middle of first millennium; cities were abandoned by end of era

"When you have major droughts, you start to get famines and unrest," says researcher

(CNN) To scuba divers and tourists, Belize's famous "Blue Hole" underwater cave is a wonder, one of the "10 most amazing places on Earth," according to the Discovery Channel.

To scientists, it's something more: evidence of the drought that is suspected to have led to the demise of the Mayan civilization.

New research reinforces that theory, Rice University Earth scientist Andre Droxler told LiveScience

The team drilled cores from the Blue Hole sinkhole and a nearby lagoon. They found that the ratio of titanium to aluminum changed in the ninth and 10th centuries, a period when the Mayan civilization in the Yucatan Peninsula went into decline. More titanium means that heavier rains were affecting the region, since the runoff from the area's volcanic rock is rich in the element.

But from about A.D. 800 to 1000, the ratio between the two elements was much smaller, indicating that there was much less rainfall.