small range of the Andes Mountains in south-central Peru, extending about 160 miles (260 km) northwestward from the city of Cuzco. The range, marked by the erosive action of rivers that have cut deep canyons, rises to 20,574 feet (6,271 metres) at Mount Salccantay (Salcantay, or Sarkantay). The most atypical of the range's peaks is Pumasillo (“Puma's Claw”), at 19,915 feet (6,070 metres); it is not an isolated peak but the culmination of a large massif. Pumasillo is not visible from surrounding villages, and, although its existence was known, it was not accurately mapped until 1956. The Vilcabamba region, the site of Machu Picchu and other extensive ruins, was the last refuge for Incas escaping from the Spanish conquistadors in the 16th century.