Incan Ruin – Machu Picchu, Peru

The Inca fortress of Sacsahuamán overlooks Cusco from a hill 755 feet above the city. The huge fortifications surrounding Cusco, built to protect and to solidify Inca control, are outstanding examples of the advanced engineering techniques of Andean peoples. Stones weighing several tons were precisely cut and placed in jigsaw-like fashion, without the aid of mortar, to form massive walls.