During his groundbreaking global expedition (1519–1522), Portuguese explorer Fernand Magellan relied on celestial navigation to navigate uncharted waters. In the Southern Hemisphere, where Polaris is absent, he adopted indigenous techniques that utilized the Southern Cross (Crux) to identify the celestial south pole.
By extending the line formed by the Southern Cross's stars, sailors could accurately determine southward orientation, enabling them to traverse unfamiliar seas with confidence.