Cusco is truly a remarkable place. Even after five hundred years, the mark of the Incan empire is still evident on the city. La Plaza de Armas, for example, has always been the central plaza, and even though cathedrals now dominate the plaza, the first level of stonework reveals the plaza’s imperial past. Many years before the Spanish came, Cusco was the capital of the Incan empire. The Incans achieved amazing feats of engineering in their time, but one of the most extraordinary things that they achieved was the building of walls. Specifically, the building of walls without mortar. There are three specific periods of Incan walls that can be found in Cusco: pre-Incan, Incan, and imperial-Incan. Pre-Incan walls are of a more rustic construction, made of small rocks held together with mortar. Incan walls are made of big and small blocks of stone, but these are carved to fit each other perfectly, so there is no need for mortar to hold the wall togther. We saw this construction a lot in Saqsaywaman, the citadel that overlooks Cusco from a hill. Finally, in imperial Incan construction, all of the blocks are identical and stay together without mortar. This construction is unparalleled in its engineering technique, and has yet to be replicated or challenged. All of the Incan walls in Cusco are built on a slant and are supported by many small rocks underneath. This is due to the area’s frequent siesmic activity. In the event of an earthquake, the small rocks allow the wall to move with the shaking of the earth, but prevent friction and eventual collapse. The slant provides a triangular base to the walls, with is much more stable than a rectangular shape, and prevents collapse as well. The way that the walls were built was through the use of several dirt ramps and logs that moved the blocks underneath. On some of the stones, you can still see the marks made by the ropes that were used to pull them into place.
When the Spanish invaded in 1536, many Incan sacred sites were destroyed and replaced with cathedrals, like the ones in La Plaza de Armas. Ninety percent of the population was killed, either because of plague and disease, or because of the exploitation of the Spanish. Because of this, many of the engineering techniques seen in the walls are now lost to history. However, the walls were so strong that they could not be destroyed completely, so the Spanish simply incorporated them into their own buildings and built the churches on top of sacred religious sites. There is also a cross made of large stones on the ground in La Plaza de Armas that commemorates the lives of Tupac Amaru I, Tupac Amaru II, and his wife Micaella Bastidas in 1572, who were executed in the plaza after their uprising against the Spanish crown. Everywhere you look in Cusco, the mark of the Incas is evident. It is the backbone and pride of the city, and will be for years to come.