What has stopped us, Ozma?
Is it magic of some sort ?" Ozma was feeling around, her bands outstretched before her.
"Yes, dear, it is magic," she replied.

"The Flatheads had to have a way from their mountain top from the plain below, but to prevent enemies from rushing up the stairs to conquer them, they have built, at a small distance before the entrance a wall of solid stone, the stones being held in place by cement, and then they made the wall invisible." "I wonder why they did that ?" mused Dorothy.

"A wall would keep folks out anyhow, whether it could be seen or not, so there wasn't any use making it invisible.

Seems to me it would have been better to have left it solid, for then no one would have seen the entrance behind it.

Now anybody can see the entrance, as we did.