Labyrinth

The maze built by Daedalus for Minos to hold the Minotaur, and the model for every enclosure designed so that what is inside cannot get out and what goes in cannot get back.

Herodotus describes a real one in Egypt, above the lake of Moeris, with twelve roofed courts and three thousand chambers, half above ground and half below. He says he saw the upper rooms himself and was not permitted into the lower, and that the building surpasses even the pyramids.

He was not allowed into the lower half because the tombs of the kings were there, and the crocodiles.