Vikings were skilled navigators, using natural elements and simple tools to guide their long journeys across open seas. They relied on landmarks along the coastline, the position of the sun and stars, and tools like sunstones, which could polarize light and determine the sun's position on cloudy days. Observing the flight patterns of birds, changes in wave patterns, and even the color of the water helped them assess proximity to land. This practical knowledge was passed down through generations and allowed them to travel vast distances, from Scandinavia to Greenland and even North America. Viking ships, with their shallow drafts and robust build, were designed for both rivers and open seas, facilitating navigation across a range of environments.