The Andes form a continuous highland belt along the western edge of South America, making them the world’s longest continental mountain range. Geographically, they are unique for their length and diversity of climates, ranging from tropical in the north to glacial in the south. This vast range was created by the subduction of the Nazca Plate. Because of their immense length, they create a massive barrier that influences the climate of the entire continent, facilitating the rain-shadow of the Atacama Desert and providing the headwaters for the Amazon River.