The Andes Mountains
The Andes Mountains form one of the longest continuous mountain ranges on Earth, extending over 7,000 km (4,400 miles) along the west coast of South America. One of the more surprising aspects of this range is how narrow it is in most places. The average width of the Andes is 200 km (124 miles), though its width ranges from 150 km (93 miles) to 640 km (398 miles) across. The height of the Andes is about 4,000 meters (13,123 feet) high, and it includes peaks above 6,000 meters (19,685 feet). Aconcagua, the highest peak in the Andes, is 6,962 meters (22,841 feet). Many of the peaks in the Andes are active volcanoes. The mountain range extends over Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela .
The Andes form a massive barrier between the eastern Pacific Ocean and the rest of the continent of South America. This barrier impacts the climate of South America, creating both wet and dry regions. The northern part of the Andes is typically rainy and warm. The west side of the central Andes is extremely dry and includes the Atacama Desert in northern Chile; the eastern portion of the central Andes is much wetter. In the south, the western side of the Andes tends to be wet, while the eastern plains of Argentina are in a rain shadow and tend to be very dry. Many of the peaks in the Andes receive heavy snowfall and contain glaciers.
The forces of plate tectonics are responsible for the formation of the Andes. The Nazca plate and a part of the Antarctic plate have been subducting beneath the South American plate, which is a process that continues today and causes earthquakes and volcanic eruptions in the region.
The Inca Empire started in Peru in the early 13th century and spread throughout the Andes in the 1400s. The Incas built roads and aqueducts throughout the mountain range. Inca engineers constructed impressive sites, including the capital city of Cuzco and Machu Picchu. In the 1530s the Inca Empire was devastated by a civil war and exposure to European diseases.