1 of 6   The Inca Architecture (Macchu Pichu) detail. Photo: Robert Lende
	THE INCA (LATE HORIZON, A.D. 1438-A.D. 1532) hen the Spanish explorer Francisco Pizarro arrived in Peru in November of 1532, he and his 600 conquistadors were astonished by the wealthy and complex civilization of the Inca. The Inca called their empire Tahuantinsuyu, Land of the Four Quarters, and at the time it was the largest nation on earth. The Inca dominated most of the territory that today comprises Ecuador, Peru, Bolivia, northern Chile, and northwestern Argentina. The Inca organized vast irrigation projects and an elaborate highway system that connected all regions in the empire. Their sophisticated and methodical state organization impressed the Spanish, while their magnificent, gold-embellished temples excited the conquistadorsÆ greed. The Inca were the most recent rulers in the Andes, but their social, political, religious, and artistic institutions shared deep roots with previous Andean societies.