Running from the high-altitude Andean city of La Paz to the subtropical Yungas valleys and the Amazonian lowlands beyond, the 64km Yungas Road involves a sharp 3,500m descent. Parts of the highway are only 3m wide; there is a series of sharp turns and blind corners; and mini waterfalls splash down the surrounding rockface. Safety barriers make only a rare appearance – far more common are roadside shrines: white crosses, bunches of flowers, yellowing photos.