The National Museum of the American Indian (part of the Smithsonian) has opened an exhibit, The Greak Inka Road: Engineering an Empire; it will be open until June 2018 (per WSJ, 10-20-2015).
My own interest in great highways is linked with my interest in civilizations; civilizations build road networks as a by-product of administering large areas; and these highways are usually the longest-lasting residues of such cultures; all of us Europeans have trod or driven on what once were Roman roads. A post of mine on South American empires is here. The Incas originated as a culture around 900 A.D. Their empire extended from 1438 to 1533—and would have lasted a great deal longer had it not been for those conquistadors. Most of the Great Inca Road was built during the period of the Inca Empire although parts of it predate Inca dominion.
The map I show is from Wikipedia (link). The system, a roughly parallel formation, has a coastal main highway (in brown) and a mountain route (in blue). The light-brown roads connecting these and branching from them were part of the system—with those crossing the mountains the most spectacular. The broken lines are today’s state borders.
Pondering this vast structure—and looking at many great pictures easily accessible by entering “Inca Road System” into Google Images—I wonder what some counterpart of mine, studying civilizations and their roads, will think of the remains of The Great American Road System two thousand years from now. Will he imagine that they were built by slaves? Such is the reflex belief we bring to the subject—although we know that most Roman roads were built by soldiers and, as best as we can determine, Inca road-building itself was based on something akin to military levies. Such levies are well known to us from medieval times—never mind the still vividly remembered draft….