One hundred and six years ago today, while searching for a lost Incan capital, a 35-year-old American explorer named Hiram Bingham was led to a mountaintop in the Urubamba valley of Peru.

Harry Bingham's father's crowning achievement was his exploration of Machu Picchu almost 100 years ago. Yet Hiram Bingham III's status as the "discoverer" of the ruins is in dispute, and the ...