Cusco, often spelled Cuzco (; ()), is a city in Southeastern Peru near the Urubamba Valley of the Andes mountain range. It is the capital of the Cusco Region and of the Cusco Province. The city is the seventh most populous in Peru; in 2017, it had a population of 428,450. Its elevation is around . The city was the capital of the Inca Empire from the 13th century until the 16th-century Spanish conquest. In 1983, Cusco was declared a World Heritage Site by UNESCO with the title "City of Cuzco". It has become a major tourist destination, hosting nearly 2 million visitors a year. The Constitution of Peru (1993) designates it as the Historical Capital of Peru. Spelling and etymology The indigenous name of this city is . Although the name was used in Southern Quechua, its origin is found in the Aymara language. The word is derived from the phrase ('rock of the owl'), related to the city's foundation myth of the Ayar siblings. According to this legend, Ayar Awqa () acquired wings and flew to the site of the future city; there he was transformed into a rock to mark the possession of the land by his ("lineage"): The Spanish conquistadors (Spanish soldiers) adopted the local name, transcribing it according to Spanish phonetics as or, less often, . was the standard spelling on official documents and chronicles in colonial times, though was also used. , pronounced as in 16th-century Spanish, seems to have been a close approximation to the Cusco Quechua pronunciation of the name at the time. As both Spanish and Quechua pronunciation have evolved since then, the Spanish pronunciation of 'z' is no longer universally close to the Quechua pronunciation. In 1976, the city mayor signed an ordinance banning the traditional spelling and ordering the use of a new spelling, , in municipality publications. Nineteen years later, on 23 June 1990, the local authorities formalized a new spelling more closely related to Quechua, Qosqo, but later administrations have not followed suit. There is no international, official spelling of the city's name. In English-language publications both "s" and "z" can be found. The Oxford Dictionary of English and Merriam-Webster Dictionary prefer "Cuzco", and in scholarly writings "Cuzco" is used more often than "Cusco". The city's international airport code is CUZ, reflecting the earlier Spanish spelling. History Killke culture The Killke people occupied the region from 900