Whither were they being led--to a dungeon?
Well, they would soon know, and at the worst it was not probable that these barbarians would harm Juanna.

They followed the tunnel or passage for about a hundred and fifty paces; at first it sloped downwards, then the floor became level till at length they began to ascend a stair.

There were sixty-one stone steps in this stairway, for Leonard counted them, each about ten inches high, and when all were climbed they advanced eleven paces along a tunnel that echoed strangely to their steps, and was so low that they must bend their heads to pass it.

Emerging from this tunnel through a narrow opening, they stood upon a platform also of stone, and once more the chill night air fanned their brows.
So dense was the gloom that Leonard could tell nothing of the place where they might be, but from far beneath them rose a hissing sound as of seething water, and combined with it another sound of faint murmuring, as though thousands of people whispered each to each.

Also from time to time he heard a rustling like that of a forest when a gentle wind stirs its leaves, or the rustling of the robes of innumerable women.
This sense of the presence of hidden waters and of an unseen multitude was strange and terrifying in the extreme.