instance, they have higher walls made of cut stones instead of rough fieldstones. This type of high-prestige terracing is also found in other Inca royal estates such as Chinchero, Pisaq, and Yucay. A set of sunken terraces starts south of Ollantaytambo's Plaza de Armas, stretching all the way to the Urubamba River. They are about 700 m long, 60 m wide, and up to 15 m below the level of surrounding terraces; due to their shape, they are called Callejón, the Spanish word for alley. Land inside Callejón is protected from the wind by lateral walls which also absorb solar radiation during the day and release it during the night; this creates a microclimate zone 2 to 3 °C warmer than the ground above it. These conditions allowed the Incas to grow species of plants native to lower altitudes that otherwise could not have flourished at this site. At the southern end of Callejón, overlooking the Urubamba River, is an Inca site called Q'ellu Raqay. Its interconnected buildings and plazas form an unusual design quite unlike the single-room structures common in Inca architecture. As the site is isolated from the rest of Ollantaytambo and surrounded by an elaborate terraces, it was postulated to be a palace built for emperor Pachacuti. Storehouses The Incas built several storehouses or qullqas () out of fieldstones on the hills surrounding Ollantaytambo. Their location at high altitudes, where more wind and lower temperatures occur, defended their contents against decay. To enhance this effect, the Ollantaytambo qullqas feature ventilation systems. They are thought to have been used to store the production of the agricultural terraces built around the site. Grain would be poured in the windows on the uphill side of each building, then emptied out through the downhill side window. Quarries The main quarries of Ollantaytambo were located at Kachiqhata, in a ravine across the Urubamba River some 5 km from the town. The site features three main quarrying areas: Mullup'urku, Kantirayoq, and Sirkusirkuyoq; all of them provided blocks of rose rhyolite for the elaborate buildings of the Temple Hill. An elaborate network of roads, ramps, and slides connected them with the main building areas. In the quarries are several chullpas, small stone towers used as burial sites in pre-Hispanic times. Defenses As Ollantaytambo is surrounded by mountains, and the main access routes run along the Urubamba Valley; there, the Incas built roads connecting the