"Surprise followed surprise until there came the realization that we were in the midst of as wonderful ruins as any ever found in Peru," he wrote. He had come upon Machu Picchu ("old peak" in ...

in northern Peru, was the largest city in the Americas and the largest adobe city on earth. Ten thousand structures, some with walls 30 feet high, were woven amid a maze of passageways and streets.

Published Jan. 13 | Read More | Beneath a bustling city in Peru, an ancient labyrinth stretching ... The subterranean maze stands as a testament to the ingenuity of the Inca civilization that ...