Why it matters
Vast stones quarried across a river and dragged up the opposite slope to a hilltop temple — engineering whose exact method still puzzles.
What mainstream says
Inca work; transport methods debated but within human capability.
The memory of it
Ollantaytambo is a hands-on test of supposedly impossible engineering. Its builders quarried multi-tonne porphyry blocks on one mountainside, moved them across a river valley, and raised them up the opposite slope into a precise temple wall. Mainstream credits the Inca and treats the transport as remarkable but human — and that is our canonical reading (grade A). Yet the exact method is still debated and the joints sit at the upper edge of what hand-tools should achieve. It belongs in the case because it shows the recurring signature: mastery of giant stone appearing fully formed, with little visible apprenticeship behind it. We grade the craft as real and keep 'lost technique' as a labelled question, never a claim.
Sources & further reading
The authoritative reference for this site/finding — and its own primary citations — so you can check us.