The Inca citadel of Machu Picchu comprises ~153 structures still standing from an estimated 200 original buildings—a remarkable 77% survival rate after 500+ years of abandonment, earthquakes, and vegetation.
Ashlar masonry – Stones cut so precisely no mortar needed; joints resist seismic shifting. Trapezoidal doors/windows – Earthquake-resistant geometry. Foundation engineering – Deep stone footings, drainage layers.
~47 structures lost to: landslides (steep slopes), root wedging (forest regrowth), colonial-era stone robbing, and early excavation damage (Bingham 1912).
Every standing wall is a testament to Inca engineering that outperforms modern code in one of Earth's most active seismic zones.