Designing a hiking trail seems simple enough: It has to take a person from A to B, pass through scenic nature, and last through years of wear and tear. And for most of human history, trails did that without much intentional design at all. But as trails shifted from essential transportation to a recreational destination, the way we make them did, too. Now, hidden in every trail is a carefully made design language of angles, alignment, and materials that keep them enjoyable for generations. Watch our video to hear trail ecologist Jeffery Marion explain how these principles work — and why they’re more important now than ever.