The dry stone masonry at Inca sites reminded me of Etruscan foundations of later Roman buildings: just supreme craftsmanship, nothing beyond human effort.
The miracle to me is how they crossed that fucking Urubamba River...just looking at the thing scared me. That River seems endlessly pissed off.
Originally Posted by Don T. Lukbak
May have been a trickle of a stream when they crossed it back then. Erosion and geology will change a landscape drastically over the course of a few years.
Human effort is highly underrated. Modern examples are the elimination of old growth stands of the long leaf pine in Texas with nothing but hand saws and axes in a couple of decades or the slaughter of 60 million buffalo in a span of 5 years.
Not a tree hugger but raw manpower can be brutally efficient with the right incentives.