The Andes run almost the entire length of South America, from Venezuela down to the tip of Patagonia. End to end they stretch around 7,000 kilometres, which makes them the longest above-water mountain range on the planet. Only an undersea range, the mid-ocean ridge, is longer.
The Andes were squeezed up where the Nazca Plate dives under South America. That same pressure makes the range volcanic, and many of its highest peaks are giant snow-capped volcanoes. The tallest, Aconcagua, reaches 6,961 metres.
People have lived high in the Andes for thousands of years. The Inca built their capital Cusco at 3,400 metres and the famous city Machu Picchu even higher. Andean people often have larger lungs and more red blood cells than people who live at sea level.
