Cusco and surroundings, Peru 2011

Coricancha. Those small upward pointing nodges just below the vertical joint give a hint for a plasticine like shapable soft stone during construction of the wall. There are stories heard by explorers like Hiram Bingham and Percy Fawcett around 1900 from the Peruvian locals about acids having been used for dissolving stones: http://www.spirasolaris.ca/waterstone.html