Qullqa

thumb|220px|right|The Inca empire and the roads which traversed it thumb|right|A complex of 27 Qullqas above Ollantaytambo, Peru A qullqa ( "deposit, storehouse"; (spelling variants: colca, collca, qolca, qollca) was a storage building found along roads and near the cities and political centers of the Inca Empire. These were large stone buildings with roofs thatched with "ichu" grass, or what is known as Peruvian feathergrass (Jarava ichu). To a "prodigious [extent] unprecedented in the annals of world prehistory" the Incas stored food and other commodities which could be distributed to their armies, officials, conscripted laborers, and, in times of need, to the populace. The uncertainty of agriculture at the high altitudes which comprised most of the Inca Empire was among the factors which probably stimulated the construction of large numbers of qullqas.

==Background== The pre-Columbian Andean civilizations, of which the Inca Empire was the last, faced severe challenges in feeding the millions of people who were their subjects. The heartland of the empire and much of its arable land was at elevations between to more than and subject to frost, hail, and drought. Tropical crops could not be grown in the short growing seasons and a staple crop, maize, could not usually be grown above in elevation. The people at higher elevations grew potatoes, quinoa and a few other root and pseudocereal crops. Herding llamas and alpacas for meat, wool, and as beasts of burden was important.