Telegraph: The climate remained dry but melting glacial ice provided a constant supply of water, resulting in a surplus of crops to feed the population. The men freed up from agricultural duties were then able to focus on other activities, among them constructing roads and buildings such as the Incas’ 3,250-mile Royal Road through the highlands, the 2,520-mile Coastal Road and Machu Picchu, the Lost City of the Incas. Dr Alex Chepstow Lusty, a British palaeoecologist working for the …