A catacomb containing 8 million mummified dogs (to honor Anubis, the jackal-headed god of the dead) also held a surprise: a 45-million year old marine vertebrate fossil on the tomb roof. No one is certain whether the Egyptians were aware of the fossil when they built the tomb.

"The ancient [Egyptian] quarry men may have been aware of it, or they may have gone straight through it, it's hard to know," said one of the researchers. The fossil is still being studied, but it is likely an ancient relative of a manatee or dugong. To the ancient Egyptians, what might it have looked like?

A stone Anubis, perhaps?