For Travel + Leisure. The ancient Qhapaq Ñan road system extends more than 18,600 miles across six countries. We traced 300 of these from Chile’s Atacama desert to Bolivia’s Salar de Uyuni salt flats - one of the most spectacular and inhospitable on the planet. At 14,000 feet the ground here is white, the water is red, and the winds whip up the sand of ancient seabeds.