<P> The section of the mountain where Machu Picchu was built provided various challenges that the Incas solved with local materials . One issue was the seismic activity due to two fault lines . It made mortar and similar building methods nearly useless . Instead , the Inca mined stones from the quarry at the site , lined them up and shaped them to fit together perfectly , stabilizing the structures . Inca walls have many stabilizing features : doors and windows are trapezoidal , narrowing from bottom to top ; corners usually are rounded ; inside corners often incline slightly into the rooms ; and outside corners were often tied together by `` L '' - shaped blocks ; walls are offset slightly from row to row rather than rising straight from bottom to top . </P>
<P> The section of the mountain where Machu Picchu was built provided various challenges that the Incas solved with local materials . One issue was the seismic activity due to two fault lines . It made mortar and similar building methods nearly useless . Instead , the Inca mined stones from the quarry at the site , lined them up and shaped them to fit together perfectly , stabilizing the structures . Inca walls have many stabilizing features : doors and windows are trapezoidal , narrowing from bottom to top ; corners usually are rounded ; inside corners often incline slightly into the rooms ; and outside corners were often tied together by `` L '' - shaped blocks ; walls are offset slightly from row to row rather than rising straight from bottom to top . </P>
where did the machu picchu stones come from
where did the machu picchu stones come from
the quarry at the site
the quarry at the site