Located on a steep hill above the city of Cuzco, the Saqsaywaman (also known as Saksaq Waman, Sacsayhuamán , Sacsahuaman, or Saxahuaman) fortress offers an impressive view of the city and the valley in which it is located. It was constructed by the Killke culture in about AD 1100, and further expanded by the Inca in 13th century and after.
Many guidebooks recommend visiting the Saqsaywaman Ruins before Machu Picchu, but I think it doesn’t matter in which order you see them. We first visited Machu Picchu, and we don’t think it took away from our experience of the Saqsaywaman Ruins. Machu Picchu is a larger site and is located in more impressive surroundings, but the Saqsaywaman Ruins are also quite impressive due to the size of the limestone stones that were used in the construction of the fortress. The largest of these blocks are estimated to weigh between 150 to 200 tons, and are among the largest used in any building in pre-Hispanic America. It is unknown how those huge blocks were put into place.
Also, the precision with which those blocks were fitted into the walls of the fortress is impressive and unmatched in the Americas. The stones are so closely spaced that–we were told–not a single piece of paper will fit between them. This precision, combined with the way the walls lean inward, is thought to have helped the ruins survive multiple devastating earthquakes, despite the fact that no mortar was used.