From our modern perspective, it's difficult to imagine a time when the earth still contained mysteries and men headed out in wooden boats on journeys into the unknown. But that was not the case during the Age of Exploration. The Great Explorers tells the dramatic stories of the four men whose expeditions helped define this era: Bartolomeu Dias, Christopher Columbus, Vasco da Gama, and Ferdinand Magellan. They were demanding and imperfect leaders, single-minded in the pursuit of their goals. Their exploits on the high seas changed the course of civilization and helped create the modern world.