Geologist's eye on Sphinx's face

Here's a riddle of the Sphinx: How old is it?

Traditional Egyptologists date the mammoth monument -- with the head of a man and the body of a lion -- to about 2,500 B.C.

But Boston University geologist Robert Schoch, who spoke to a group of ancient-Egypt enthusiasts Saturday at the Wichita Museum of World Treasures, says his analysis shows the Sphinx got started at least two millennia earlier.