Ancient Polynesian wayfinders relied on their memories and an intricate knowledge of ocean patterns, celestial phenomena and observations of birds in flight to make long-distance ocean crossings.
This video from TED-Ed explains how they found their way:
A group of practitioners in Micronesia have worked to keep this tradition alive. These navigators have shared their knowledge with crewmembers aboard the voyaging canoe Hokule’a. Since 1976, Hokule’a has sailed more than 160,000 miles using Polynesian wayfinding.