Why do the Andes exist? Why is it not a place of lowlands or narrow seas? Wouter Schellart, a geophysicist at the Vrije Universiteit Amsterdam, has been pondering these questions for more than a decade. Now, he has found the answers using an advanced computer model. “It’s a matter of enormous size, longevity and great depth”, he said. “These aspects made the Andes the longest and second-highest mountain belt in the world.”