Admire the fortress of Sacsayhuaman and the astonishing of its walls composed of huge stones assembled with great precision, know the adoration of Kenko, the watchtower of Puca Pucara and finally Tambomachay, ancient Inca enclosure of worship to the water. Sacsayhuamán is one of the most amazing buildings in the world. It is thought that it began to be built during the government of the Inca Pachacutec in the fifteenth century. It is believed that more than 20,000 men extracted the stones from the nearby quarries and moved them 20 kilometers to the hill in the city of Cusco. Today, it is estimated that Sacsayhuaman retains only 40 percent of its old structure. Even so, the site has structures up to 125 tons in weight. How did the Incas build Sacsayhuaman with structures of unimaginable weight and size for the time? Many questions are still a mystery. Therein lies the beauty of this archaeological site.