Above Cusco is the ancient Inca site of Saqsaywaman, reached via set of steep (but not as steep as on the trail) from Cusco.
Also know as Saqsaywaman, Sacsayhuamán, Sacsayhuaman, Sacsahuaman, Saxahuaman, Saksaywaman, Sasawaman, Saksawaman, Sacsahuayman, Sasaywaman or Saksaq Waman according to Wiki.
The site is not far from the Cristo Blanco, a white statue of Christ which looks down over Cusco.
The above is sadly the last (for now I hope) image taken with my Tamron 18-200 which stopped working from this point meaning every other shot was taken with a 24mm Canon Prime.
The stratigraphy of the rock would probably mean more to me if I new more about geogology, it is certainly at a right angle to the current ground and polishes nicely for fun sliding up and down.