National Geographic : 1913 Apr
Photo by Hiram Bingham A HUGE ROCK IN THE DEFENSES OF MACHU PICCHU The moat is still from 6 to 8 feet deep, but has probably been partly filled up by the accumulations of centuries. In places unusually large rocks were used in the construction of the inner wall of the moat (see pages 446 and 453). Photo byHiram Bingham THE DEFENSES OF MACHUPICCHU: THE INNER WALL Besides the moat, the inner defenses ofMachu Picchu consisted of a high wall strongly built oflarge, rough boulders. The Incas were good engineers and thoroughly understood theartofdrainage. In this picture of the wall may beseen two outlets forwater, per mitting the terraces within the wall tobeproperly drained.