The history of cosmic ray research is a story of scientific adventure. For nearly a century, cosmic ray researchers have climbed mountains, ridden hot air balloons, and traveled to the far corners of the earth in the quest to understand these fast-moving particles from space. They have solved some scientific mysteries - and revealed many more. With each passing decade, scientists have discovered higher-energy, and increasingly more rare, cosmic rays. The Pierre Auger Project is the largest scientific enterprise ever conducted in the search for the unknown sources of the highest-energy cosmic rays ever observed.