Qhapaq Ñan, Andean Road System

Long before Europeans reached South America, the Incas stitched an empire together with roads — some 30,000 km of them, climbing past peaks above 6,000 metres and crossing deserts, valleys and rainforest. Qhapaq Ñan, the Andean Road System, entered the UNESCO World Heritage List in 2014 as a series of 273 sites shared by six countries, Argentina among them. Paved ways, staircases and waystations preserve the engineering that carried goods, armies and messages across the world's most demanding terrain.