Curiosity about what's over the horizon is one of humanity's most distinctive traits. From Christopher Columbus and Ferdinand Magellan to Yuri Gagarin and Neil Armstrong, our curiosity has taken us to ever more distant lands. But we'd never have gone anywhere without engineers and engineering. Whether traversing the seas, great landmasses, or deep space, we depended on ships, telescopes, guidance systems, engines, and a myriad of other devices to help us find our way. The story of exploration is one of courage and curiosity — along with a good dose of sophisticated engineering.