This image captures several states of construction: to the left is the perfect high Inca construction. At the center are the same stones, but which have been deconstructed, then carelessly stacked by the colonizers. To the right and bottom are rubble walls stack haphazardly post-Inca.
The churches in Cusco were all built on Inca foundations, usually with stones plundered from Inca buildings
Today, Cusco is a wonderful town for walking and living