The mountain range that runs parallel to the western coast of South America is the Andes Mountains. This extensive range stretches over 7,000 kilometers, making it the longest continental mountain range in the world. The Andes are known for their diverse ecosystems, from tropical rainforests to arid plains, and are home to unique wildlife and flora. They significantly influence the climate and culture of the regions they traverse, including Peru, Chile, and Argentina. The Andes also host ancient Inca sites, including Machu Picchu, adding to their cultural significance.