The Tahuantinsuyo
The greatest and oldest empire, developed in the American continent and that had the city of Cusco as its headquarters, goes back to the year 1200 A.C. The word Tawantinsuyo comes from a name composed by two Quechua terms: Tawa, which means four; and Suyo, which means StateThe Incas' Andean dominance was achieved through formidable organization and a highly developed economic system. The Incas rapidly expanded their empire first through political alliances and absorption, and then by swift military conquest. Though the Incas imposed their social structure and way of life, they also assimilated useful skills and practices, even granting administrative positions to defeated nobles of the Chimú and other cultures. The Incas thus succeeded in achieving political and religious unification across most of their domain.

The Incas recorded an astounding
level of achievement. They never developed a system of writing, but they kept extraordinary records with an accounting system of knots on strings, called quipus. They laid a vast network of roadways, nearly 32,200km (20,000 miles) total across the difficult territory of the Andes, connecting cities, farming communities, and religious sites. A network of runners, called chasquis, operated on the roads, relaying messages and even transporting foodstuffs from the coast to the Andes. Tambos, or way stations, dotted the highways, serving as inspection points and shelters for relay runners. The Inca Trail was a sacred highway, connecting the settlements in the Urubamba Valley to the ceremonial center, Machu Picchu.

The Incas' agricultural techniques
were exceedingly skilled and efficient, with advanced irrigation systems and soil conservation. The Incas were also extraordinary architects and unparalleled stonemasons. Inca ruins reveal splendid landscaping and graceful construction of perfectly cut stones and terraces on inaccessible sites with extraordinary views of valleys and mountains.

A rigid hierarchy and division of labor ruled Inca society. At the top, just below the Inca sovereign (who was also the chief military and religious figure and considered a descendant of the sun), was the ruling elite: nobles and priests. Tens of thousands of manual laborers provided the massive manpower necessary to construct temples and palaces throughout the empire. The Inca kept chosen maidens, or Virgins of the Sun (acllas), who serviced him and Inca nobles.

Extraordinarily tight community organization
was replicated across the empire. At the heart of the structure was the Inca's clan, the panaca, composed of relatives and descendants. Spanish conquistadors chronicled a dynasty that extended to 12 rulers, from Manco Cápac, the empire's founder in 1200 who was said to have risen out of Lake Titicaca, to Atahualpa, whose murder in Cajamarca by Spanish conquerors spelled the end of the great power.

The Inca Pachacútec
ruled from 1438 to 1463, and he is considered the great builder of Inca civilization. Under his rule, Cusco was rebuilt, and some of the most brilliant examples of Inca architecture were erected, including Cusco's Qoricancha (Temple of the Sun), the Ollantaytambo and Sacsayhuamán fortresses, and, of course, the famed religious city of Machu Picchu. Pachacútec also initiated the empire's expansion. It was Pachacútec's successor, Tupac Yupanqui (1463-93), however, who achieved dominance from Ecuador to Chile. A great conqueror, he defeated his Chimú rivals in northern Peru.

After the death of the Inca Huayna Cápac in 1525, civil war ensued, brought on by the empire splitting between his two sons, Atahualpa and Huáscar. The Spaniards, arriving in northern Peru in 1532, found a severely weakened empire -- a pivotal reason the Incas so swiftly succumbed to a small band of invading Spaniards. Another key was the Spaniards' superior military technology. Against cannons and cavalry, the Incas' slings, battle-axes, and cotton-padded armor stood little chance. But their defeat remains puzzling to most visitors to Peru, not to mention many scholars.