The really curious thing about this sort of story is that the Ancient Egyptians were telling them, too. Since a good friend has borrowed my collection of original source texts in translation, I can't give more detail, but when Khufu wanted to build the pyramids, he had heard that there were underground tunnels, and sent for someone who might know the secret. But he kept what they told him secret, too!

The theories of some modern writers,
Are stranger than anyone thinks,
At the height of the silly season,
They set off to measure the sphinx.

Adapted from a parody of something a nice girl like me wouldn't know, by the above mentioned friend.

Penny