development. (Exceptions are northern Chile near the Atacama region, which
may correspond to an earlier frontier or to an area where special vigilance was
necessary, and the Calchaquí area in Argentina, where Inca forts safeguarded
valuable metallic ore extraction and production; see Metallurgy; Mining).
The hilltop fortress of Quitaloma formed part of a chain of forts overlooking the
basin of Quito, Ecuador, and witnessed battles between Inca and Cayambe
warriors over several decades. Photo courtesy of Samuel Connell and Chad
Gifford.The distribution of Inca forts is uneven, with some frontiers much more
heavily fortified than others: the northern frontier in Ecuador, the eastern rim of
the highlands in Bolivia, some distance within the southeastern frontier in
Argentina, and near the southern limits of Tahuantinsuyu in Chile. Forts have not
been reported on the poorly studied eastern frontier in Peru. In some cases, the
Incas reutilized earlier native forts after their capture; this pattern is particularly
common in the southern empire. In other cases, they built new fortifications, as
in Ecuador. The patchy distribution of Inca strongholds shows they were not