14 Mysterious Landmarks That Science Still Can't Fully Explain

11. Saksaywaman (Cusco, Peru): The Imperfectly Perfect Inca Walls

High above Cusco, Peru, stands Saksaywaman, a colossal Inca fortress whose massive, perfectly interlocking stone walls defy conventional architectural explanation. Some polygonal blocks weigh over 100 tons, yet they fit together so precisely, without mortar, that a single sheet of paper cannot be inserted between them. The ingenious "puzzle-piece" construction, including convex and concave angles, makes the walls incredibly earthquake-resistant. However, how the Inca civilization cut, transported, and meticulously fitted these immense stones with such perfection, using only basic tools, remains a baffling engineering feat that science still cannot fully replicate or explain.