Peru as loose confederation of cities scattered along the coast of northern Peru and southern Ecuador, the Chimu flourished from about 1140 to 1450. Their capital was at Chan Chan outside of modern-day Trujillo. In the highlands, both the Tiahuanaco culture, near Lake Titicaca in both Peru and Bolivia, and the Wari culture, near the present-day city of Ayacucho, developed large urban settlements and wide-ranging state systems between 500 and 1000 AD. In the 15th century, the Incas emerged as a powerful state which, in the span of a century, formed the largest empire in pre-Columbian America with their capital in
Pre-Columbian savannas of North America and 1940s stopped much of the regular burning which the savanna required. By the latter half of the 20th Century many researchers had rediscovered both the prehistoric use of fire and methods to practice burning, but by then almost all prairie and savanna lands had been converted to agriculture or succeeded to full-canopy forest. Modern conservation of savanna includes controlled burning, and at present about a year are burned. Pre-Columbian savannas of North America Pre-Columbian savannas once existed across North America. These were created by both natural lightning fires and by Native Americans. The arrival of European settlers caused the