13. The mighty walls of the citadel of Sacsayhuamán were NOT built by aliens using anti-gravity devices
Sacsayhuamán is a citadel complex located near Cusco, the historic capital of the Inca Empire in Peru. Initially constructed by the Killke people between 900-1100 CE, it was expanded by the Inca from the 13th century. Among its important features, the terraced walls of Sacsayhuamán, approximately 400 meters in length and 6 meters tall, are constructed from approximately 200 ton stone blocks so precisely interlocked that the gaps between them are less than that of a single piece of paper; this flawless design has allowed the wall to survive major earthquakes in the region, whilst modern structures have collapsed.
Due to the impressive architectural nature of these mighty walls, stacked akin to a jigsaw, it has been contested that Sacsayhuamán could only have been constructed by an ancient civilization with assistance from a technologically advanced life-form. However similar walls exist throughout the historic Inca Empire, including in nearby Cusco, with the civilization widely recognized as highly skilled at complicated and intricate construction. Furthermore, an archeological study has uncovered evidence of a rope-and-lever system used by the Inca for quarry transportation, dismissing claims of the immovability of such weights without anti-gravity technology.