What impressed them most was the tremendous masses of masonry, parapets and guns. In whatever direction the boys glanced their eyes rested on the frowning muzzles of big guns.
"How would you like to have all those guns turned on a ship in which you were?" asked Dan.
"If they all shot straight it would be all day with us. But, Dan, don't you think that rock is a pretty good mark itself?"
"Yes. And if it is all like what it is here at the bottom, I think a shot from a seven or eight-inch would crumble it. I——"
"Look!" cried Sam.
What appeared to be a basket of some sort was rising in the air far above their heads.
"What is it?"
"It looks like some kind of air-ship. But that cannot be possible."
"There's some one in it!"
"Are you sure?"