Reconstruction of a local Inca food storage deposit uncovered near Rancagua These were qolqas; Inca food storage deposits built to ensure adequate provisions for long stretches of time. The Pukara is distinct from other such forts in Chile for its notable abundance of them. Soldiers here were posted for long periods of time in the face of frequent attack, harassment and food shortages. Although the Pukara was on the Kapak Ñam, and thus on a route frequented by Inca armies, the road was also used by marauding Mapuche warriors who destroyed the crops of local Picunche tribes west of the road. These raids on crops in the area explain why the Pukara has so many qolqas and why it was so heavily fortified. Although primarily for storage, some qolqas on the site also served interesting secondary purposes. At one qolqa, archaeologists found rocks used for pulverizing crops, an Inca mill. Another was an Inca biological weapons factory; a qolqa used for storing arrowheads and poison to dip them in. This corroborates the frequency of battles and attacks here.