On our first weekend trip, we made a stop at Sacsayhuamán, a fortress located on the outskirts of Cuzco. I was most impressed by the Incan architecture and engineering shown in Sacsayhuamán. The fortress is made up of large, perfectly smooth stones that fit carefully and tightly together. Without the use of advanced technology, including the wheel, the Incas were able to bring the giant rocks to this area and carve them. Using logs, the rocks were rolled up to their final location, and were meticulously shaped using stone tools. The precise and innovative engineering methods used by the Incas are extraordinary.