@cicerone imposter,
If I were on the path in either of those photos, I would probably be literally scared to death. I'm somewhat acrophobic anyway in more ordinary places.
On the other hand, once when we were in Guatemala going up a vertiginous grade in a rickety bus, there were Mayans carrying very heavy stuff up all that way on foot. I suppose their lungs and muscles are used to it, and they have the immense need to do that lift and carry to survive, survival a good motive. Which remind me of the Sebastiano Salgado photo of the goldminers (no link).