The document provides biographical information on various explorers and firsts they achieved throughout history. It describes explorers such as Earl Shaffer who was the first to hike the entire Appalachian Trail, Gilbert Blane who discovered that citrus prevented scurvy in sailors, and Neil Armstrong who was the first man to walk on the moon. The explorers overcame various hardships in their personal lives and journeys such as poverty, illness, conflicts with others, and dangers of uncharted territories.