"In their heyday the Inca ruled over the largest land empire in the Americas, reaching the pinnacle of South American civilization. Known as the 'Romans of the Americas', these fabulous engineers converted the vertiginous, challenging landscapes of the Andes into a fertile region able to feed millions, alongside building royal estates such as Machu Picchu and a 40,000-kilometre road network crisscrossed by elegant braided-rope suspension bridges....