Cuzco (also spelled Cusco) is a city in southeastern Peru, just in the western beginnings of the Andes mountains. It is the largest city in rural Peru (350,000 as of 2007) and was probably the first large city that existed in all of South America.
The city was the capital of the massive Inca Empire from 1200 until the arrival of the conquistadors in the 1530s. Even before that, the ancient Killke peoples used Cuzco as their capital from about 900 to 1200. Most of Cuzco today is the result of the Spanish colonial period, as the Spanish built churches and palaces over the temples and homes of the old Inca rulers. Cuzco was very important to the Spanish and flourished during the colonial period.
The great Inca ruin of Sacsayhuaman, which was probably first built by the Killke peoples, is often considered a far greater example of Inca engineering genius than anything found at Machu-Picchu. Today it is believed, that Sacsayhuaman was a military fortress of some kind. Others believe that this was rather a temple dedicated to the Sun God. But whatever it was, boulders as large as 125 tons have been seamlessly fitted together with accuracy that stuns modern engineers.
Cuzco lies at 10,800′ altitude, more than 2,000′ higher than Machu-Picchu. The valley the densely populated city fills is surrounded by beautiful mountains, a delight to tourist eyes but often an obstacle when flying in or out during inclement weather.