No sign of life was visible in the great rambling palace that loomed high above them. The rows of lanceolated openings, that in the distance appeared to be ordinary windows, upon a nearer view proved to be unglazed--or, if they were fitted with glass it was too thick to reveal to an outsider the interior of the palace. That some kind of vitreous substance filled these openings was evident from the flashes of light reflected on their surface. Considering the antiquity of the building, however, and the unknown methods and materials employed by its architect, it was more likely that the substance used for windows was a crystal gathered, perhaps, from the queen's garden--the flower from those alluring bushes that had first caught Una's attention--rather than manufactured glass that must have been unknown to these Andean cavemen. Even though the first zipa was the reputed offspring of stars or condors, it was not likely that in building his palace thousands of years ago--to quote Narva's estimate--he had been able to fit it with modern improvements. Owing to the thickness of these windows, therefore, it was impossible to make out anything of the interior of the apartments of the palace for which they were, apparently, intended to serve for light. A close approach, right under the palace walls, revealed nothing more than could be seen at a distance; and as Narva avoided the great central entrance, it appeared to Una that the mystery which so fascinated her was to remain unsolved. An abrupt angle in the building, however, brought them suddenly within a little portico, extending between two massive towers jutting out from the main structure, the existence of which came as a complete surprise. On the side of this portico away from the palace clung a vine of pale green foliage, starred with white and crimson flowers similar to those in the Queen's Garden, forming with its delicate festoons a cloistered way that had a subtle attractiveness amidst the imposing lines and columns of the huge edifice rising above it. Here Narva and her companion paused, listening to the wild melody coming to them in a clear rush of sound. At the other end of the portico, leaning against the side of a long latticed window standing partly open, they could see the singer, her face turned to the apartment within, one arm encircling a lyre-shaped instrument the strings of which were lightly touched by the fingers of her right hand. The long white drapery in which she was clothed scarcely stirred with the movement from her playing, while the upward poise of her head, with its masses of dark hair flowing downward over her shoulders, indicated the rapt intensity with which she voiced the passion of her song. Apparently she was alone. The semi-obscurity of the apartment, however, at the entrance to which she stood, might have screened effectively from an outsider any one who was within.