Every year the haunting stone ruins on the steep eastern slope of the Peruvian Andes are pummeled by up to 230 in. of rain. Getting to the site, 300 miles north of Lima, requires a five-day trudge through some of the highest tropical jungle in South America, a haven for jaguars, spectacled bears and giant anteaters.
Last week a University of Colorado scientist announced that he had recently led an expedition on that grueling trek. Reason: to launch a new study of what could be one of the magnificent "Lost Cities" of the Andes. The remarkably well-preserved complex, known as Gran...