Trying to adjust her stride to the low, gliding walk required by her greatly reduced weight, Cynthia looked around furtively, thinking of escape but attempting to make her glances seem like the simple curiosity that would be natural to a visitor to a new world. Clearly the tunnel had been carved by machine from solid rock, though now and then sections of metal or a mix of broken stone smoothed and filled in with concrete indicated places where the original material had been loose or unstable, whether from the shattering effect of the meteoric bombardment, from volcanism, or merely from accidents of digging. The arched ceiling, hung with lights at semi-regular intervals, was perhaps ten or twelve feet at the center, tall enough to help offset the claustrophobia that in such an underground w
