WROCŁAW, POLAND—The Inca used two main units of measurement while constructing Machu Picchu, according to a Science in Poland report. Anna Kubicka of the Wrocław University of Science and Technology analyzed measurements of buildings at the site collected during field research conducted by the staff at Machu Picchu National Archaeological Park, the 3-D Scanning and Modeling Laboratory at the Wrocław University of Science and Technology, and the University of Warsaw between 2010 and 2017. Kubicka then calculated an indivisible unit of measurement that, when multiplied, equaled the length of different elements of Machu Picchu’s structures. She determined that two units of measurement were used: one about 16.5 inches long, and another about 21.3 inches long. The smaller unit, roughly the length of a human arm to the elbow, was used to construct farm buildings, workshops, and structures for the servants of the Inca elite. The larger unit, which does not correspond with a human body part, was used to construct buildings for elites. These structures may have been built under the supervision of imperial engineers who had their own system of measurement, Kubicka explained. Further research will see if the units of measurement were used at other Inca sites, and if they changed over time, she added. To read about a carved totem that might have been worshipped in a Peruvian temple centuries before the Inca conquered the area, go to "Idol of the Painted Temple."