In 1911, a US professor claimed he found the secret mountain stronghold of the last Incan king. 53 years later, a new explorer proved him wrong – and the BBC followed in his footsteps.
High on the Bolivian altiplano sit blocks of stone so cleanly cut that visitors routinely assume a machine shaped them. The ...
Early farmers achieved an "engineering wonder of the world" by building a giant irrigation system in South America thousands ...