Encyclopedia of the Incas

Two roads formed the backbone of the system: a highland road and a parallel
coastal road. The highland road ran from a point just shy of the modern Ecuador-
Colombia border, down through the Peruvian highlands, skirting Lake Titicaca
and south into what is today northwestern Argentina. The coastal road, on the
other hand, ran from Tumbes, in what is today northern Peru, through desert
punctuated by the occasional lush river valley, down through one of the world’s
most arid deserts, the Atacama, and on to Santiago, Chile. A dozen or more
lateral roads linked the two main north-south roads, while still others headed into
the cloud forest flanking the eastern slopes of the Andes. Some roads, among the
highest ever built, led to mountaintop sanctuaries, towering more than 5,000
meters (16,400 feet) above sea level (see Capac Hucha).
By all accounts, the most spectacular road of all linked Cuzco to Quito,
passing along the backbone of the Andes through Chinchaysuyu, the
northwestern quadrant of the empire. This is the road most early chroniclers
traveled, and all described it in superlatives. “Oh,” said Pedro de Cieza de
Leon, writing in the 1540s, “Can anything comparable be said of Alexander, or
of any of the mighty kings who ruled the world, that they built such a road . . .”
(Cieza 1959 [1553]). Its importance and formal construction may reflect the
focus in late Inca times on conquests in Ecuador. Indeed, the Inca ruler Huayna
Capac is said to have rebuilt sections of the road, initially constructed by his
father, Topa Inca Yupanqui. No other road featured more Inca centers, boasted
longer stretches of formal construction or the greatest widths (at times the road is
16 meters [50 feet] wide), embellished with stone paving, culverts, drainage
canals, and causeways that raised the road surface above swampy ground. Steep
sections of road were negotiated with flights of steps, built of fieldstone.
(Because Andean people did not have the wheel, roads did not need to
accommodate wheeled vehicles, and steps were an easy solution to especially
steep slopes).
The width of the road varied according to the importance of the road and the
terrain it traversed. In the high jungle or cloud forest, the Incas built daring
cobbled roads that clung to cliff sides, with steps and tunnels often carved into
the living rock, such as the 20-meter-long (65-foot-long) tunnel cut through solid
granite on the road between Puyu Pata Marca and Saya Marca, en route to
Machu Picchu. There, the steep and rugged terrain forced engineers to design
narrow roads 1–3 meters (3–10 feet) wide. On the desert coast, where it seldom
rains, the road was rarely paved, and generally used a less formal construction
than its highland counterpart. Some sections of coastal road, however, included